Background

This is a benign tumor of the bone. Its importance lies in recognizing the characteristic histology which at times may mimic many other bone tumors including osteosarcoma. The cause of this tumor is still unknown although several studies have documented intranuclear virus-like particles. These tumors present with pain, usually with a mass and swelling. About 10% of patients present with a pathologic fracture. Local recurrences may occur if there is an inadequate initial treatment.

OUTLINE

Epidemiology
Disease Associations
Pathogenesis
Laboratory/Radiologic/Other Diagnostic Testing
Gross Appearance and Clinical Variants
Histopathological Features and Variants
Special Stains/ Immunohistochemistry/ Electron Microscopy
Differential Diagnosis
Prognosis
Treatment
Commonly Used Terms
Internet Links

EPIDEMIOLOGY	CHARACTERIZATION
INCIDENCE	5% of all biopsied bone tumors 20% of benign tumors 6th most common primary osseous neoplasm
AGE RANGE-MEDIAN	Peak 3rd decade of life <20 years in 10-15% of patients
SEX (M:F)	1:1.3

 

DISEASE ASSOCIATIONS	CHARACTERIZATION
Paget's disease of the bone

 

PATHOGENESIS	CHARACTERIZATION
Intranuclear virus-like inclusions
Cytogenetic analysis	Random abnormalities in 14 and 6
Monocytic differentiation	Most studies favor this as the cell of origin
CYCLIN ALTERATIONS
Cyclin alterations in giant cell tumor of bone. Kauzman A, Li SQ, Bradley G, Bell RS, Wunder JS, Kandel R. Department of Pathology and Laboratory Medicine (AK, SQL, RK) and University Musculoskeletal Oncology Unit, Mount Sinai Hospital (RSB, JSW).	Mod Pathol 2003 Mar;16(3):210-8 Abstract quote Cyclins play an important role in regulating the passage of dividing cells through critical checkpoints in the cell cycle. Because alterations of several cyclins, especially cyclin D1, have been implicated in the development of many human neoplasms, we examined 32 cases of giant cell tumor of long bones for cyclin D1 gene amplification and protein overexpression using differential polymerase chain reaction and immunohistochemistry, respectively. In addition, the expression of cyclin D3, cyclin B1, and the proliferation-associated antigen Ki-67 (MIB-1) was assessed immunohistochemically. Low-level cyclin D1 gene amplification was detected in 61% of giant cell tumor cases. All tumors showed cyclin D1, cyclin D3, cyclin B1, and Ki-67 (MIB-1) staining; however, the distribution was very characteristic. Cyclin D1 protein expression was seen predominantly in the nuclei of the giant cells, with occasional mononuclear cells staining. There was no correlation between cyclin D1 gene amplification and protein overexpression. Cyclin D3 staining showed a similar distribution, with 88% of cases showing protein overexpression. Cyclin D1 and/or D3 staining in the giant cells was never associated with staining for either cyclin B1 or Ki-67 (MIB-1), as the expression of the latter two proteins was restricted to the mononuclear cells. Cyclin B1 overexpression was seen in 44% of cases. Ki-67 (MIB-1) staining was present in all cases, and between 10 to 50% of the mononuclear cells were positive. These results suggest that alterations in cyclin D1 and/or D3 might play a role in the pathogenesis of giant cell tumor of bone.
MICROPHTHALMIA-ASSOCIATED TRANSCRIPTION FACTOR EXPRESSION
Immunohistochemical evaluation of microphthalmia-associated transcription factor expression in giant cell lesions. Seethala RR, Goldblum JR, Hicks DG, Lehman M, Khurana JS, Pasha TL, Zhang PJ. 1University of Pennsylvania Medical Center, Philadelphia, PA, USA.	Mod Pathol. 2004 Dec;17(12):1491-6. Abstract quote Microphthalmia-associated transcription factor (Mitf), a member of the helix-loop-helix transcription factor subfamily, normally expressed in mononuclear and multinucleated osteoclasts, is involved in the terminal differentiation of osteoclasts. Dysfunction of osteoclast activity resulting from abnormal Mitf expression has been implicated in osteopetrosis. Numerous other giant cells of various types including osteoclast-like giant cells seen in various tumors, traditionally thought to be monocyte derived, are seen in a variety of bone and extraosseous lesions. Using a monoclonal antibody with a standard immunohistochemical technique on paraffin sections, we evaluated expression of Mitf in 89 various giant cell lesions including giant cell tumor of bone (n26), giant cell tumor of tendon sheath/pigmented villonodular synovitis (n24), giant cell reparative granuloma (n3), aneurysmal bone cysts (n11), chondroblastomas (n7), foreign body giant cell reaction (n10), and sarcoidosis (n8). We also evaluated three cases of osteopetrosis and 27 various tissues without monocyte-derived giant cells (nine bone marrows, nine products of conception, seven lymph nodes with sinus histiocytosis, one granulation tissue and one thymus). Nuclear Mitf immunoreactivity was evaluated. Mitf was variably expressed in the monocyte-derived giant cells and/or the adjacent mononuclear cells/histiocytes in 23 (89%) giant cell tumors of the bone, 23 (96%) giant cell tumors of tendon sheath/pigmented villonodular synovitis, three (100%) giant cell reparative granuloma, eight (73%) aneurysmal bone cysts, five (71%) chondroblastomas, eight (80%) foreign-body giant cell reactions, and six (75%) sarcoidoses. No Mitf immunoreactivity was detected in cases of osteopetrosis and giant cells of nonmonocyte origin. Mitf immunoreactivity is rare in tissues with rich mononuclear cells/histiocytes but no monocyte derived giant cells. These findings support the notion that giant cells in giant cell lesions are likely derived from adjacent mononuclear cells and Mitf might play a role in the multinucleation process of such cells.
RANKL (RECEPTOR ACTIVATOR FOR NUCLEAR FACTOR kb LIGAND)
Phenotypic and molecular studies of giant-cell tumors of bone and soft tissue. Lau YS, Sabokbar A, Gibbons CL, Giele H, Athanasou N. Department of Pathology, University of Oxford, Nuffield Orthopaedic Centre, OX3 7LD Oxford, UK.	Hum Pathol. 2005 Sep;36(9):945-54. Abstract quote   Giant-cell tumor of bone (GCTB) and giant-cell tumor of soft tissue (GCTST) are tumors that contain a prominent osteoclastlike giant-cell component. The precise relationship between these morphologically similar tumors is unclear, and the cellular mechanism whereby giant cells accumulate within these and other locally aggressive tumors is uncertain. In this study, we have examined the cytochemical, functional, and molecular phenotype of the mononuclear and multinucleated components of GCTB and GCTST. Giant cells in GCTB and GCTST exhibited an osteoclast phenotype expressing tartrate-resistant acid phosphatase and vitronectin receptor and being capable of lacunar resorption. The mononuclear stromal cells derived from GCTB and GCTST exhibited an osteoblast phenotype, expressing alkaline phosphatase, and the receptor activator for nuclear factor kappaB ligand (RANKL), a factor that is essential for osteoclast formation. These cells also expressed osteoprotegerin (OPG), an inhibitor of osteoclastogenesis, and TRAIL, a receptor that binds OPG. Lacunar resorption by giant cells isolated from GCTB and GCTST was inhibited by OPG, zoledronate, and calcitonin. These findings indicate that the mononuclear and giant-cell components of GCTB and GCTST have similar phenotypic features and that the accumulation of osteoclasts in these giant-cell-rich tumors occurs by a RANKL-dependent process. RANKL expression by osteoblastlike mononuclear stromal cells in these tumors stimulates osteoclast formation and resorption; this would account for the osteolysis associated with these giant-cell-rich tumors. Inhibitors of osteoclast formation and activity are likely to be effective in controlling the osteolysis associated with GCTB and possibly other giant-cell-rich lesions.
RANK (Receptor Activator of Nuclear Factor kappa B) and RANK Ligand Are Expressed in Giant Cell Tumors of Bone Sophie Roux, MD, PhD Larbi Amazit Geri Meduri, MD Anne Guiochon-Mantel, MD, PhD Edwin Milgrom, MD, PhD and Xavier Mariette, MD, PhD	Am J Clin Pathol 2002;117:210-216 Abstract quote In giant cell tumors of bone (GCTBs), the mesenchymal stromal cells are the neoplastic cells and induce recruitment and formation of osteoclasts (OCs). Studies on recently discovered members of the tumor necrosis factor receptor-ligand family have demonstrated a crucial role of RANKL (receptor activator of nuclear factor kappa B [RANK] ligand) expressed by osteoblast/stromal cells and of its receptor RANK expressed by OCs during OC differentiation and activation. OCs typically are present in large numbers in GCTBs, suggesting that these tumors may contain cells expressing factors that stimulate OC precursor recruitment and differentiation. We used immunohisto-chemical analysis to study RANKL and RANK expression in 5 GCTBs. Multinucleated cells and some mononuclear cells showed strong positive staining with anti-RANK antibodies; RANKL was present in a subset of mononuclear cells that did not express the hematopoietic lineage cell marker CD45, a feature that identified them as mesenchymal tumor cells. Our results suggest that RANKL expression may have a role in the pathogenesis of GCTBs and in the formation of the large OC population present in these tumors.
STROMAL CELLS
The origin of the neoplastic stromal cell in giant cell tumor of bone. Wulling M, Delling G, Kaiser E.	Hum Pathol. 2003 Oct;34(10):983-93 Abstract quote.   Fibroblastlike stromal cells, which are always present as a component of giant cell tumor of bone (GCT), can be observed in both in vivo and cultured cell samples. Although they are assumed to trigger the cancer process in GCT, the histogenesis of GCT stromal cells is poorly understood. It is known that mesenchymal stem cells (MSCs) can develop to osteoblasts. Evidence has been presented that GCT stromal cells can also develop to osteoblasts. A connection between MSCs and GCT stromal cells was sought by using 2 different laboratory approaches. First, immunohistological analyses revealed that some of the same markers, detected by the SH2, SH3, and SH4 antibodies and the CD166 antigen, were found in GCT stromal cells as in the first developmental stages of osteoblast differentiation from the initial MSCs. These immunohistological findings could be confirmed by reverse transcriptase polymerase chain reaction. Second, cellular differentiation by morphology and lineage-specific staining offered evidence that not only osteoblasts, but also chondroblasts and adipocytes, could be cultured from stromal cells. The presented double approach indicates that GCT stromal cells can originate from MSCs.

 

LABORATORY/ RADIOLOGIC/	CHARACTERIZATION
Serum chemistries	Elevated alkaline phosphatase with normal calcium may indicate a giant cell tumor arising within Paget's disease
Radiographs	Epiphyseal tumors with metaphyseal extension Lytic tumors with fine to coarse trabeculations and discrete, well-defined borders
Stage 1	Benign latent giant cell tumors Static pattern of growth without features of local aggressiveness
Stage 2	Benign active tumors Clinically symptomatic Expansile radiolucent lesions frequently altering the contour of the bone
Stage 3	Aggressive tumors Symptomatic and rapidly growing, often associated with a pathologic fracture Angiography shows hypervascularity Radionuclide scans show intense activity Lytic lesion destroying the surrounding medullary bone and cortex

 

GROSS APPEARANCE/ CLINICAL VARIANTS	CHARACTERIZATION
General	>75% located near the articular end of a tubular bone 50% occur around the knee Distal radius Proximal femur Proximal humerus Distal tibia
Appearance	Hemorrhagic often resembling an aneurysmal bone cyst Other tumors may be soft, tan, and fleshy
Cases associated with Paget's disease	Usually arise within flat bones like the jaw
Multifocal tumors	May be associated with a more aggressive clinical course May be more common in the small bones of the hands and feet
LARYNX
Giant Cell Tumor of the Larynx: A Clinicopathologic Series of Eight Cases and a Review of the Literature Jacqueline A. Wieneke, M.D., Francis H. Gannon, M.D., Dennis K. Heffner, M.D. and Lester D. R. Thompson, M.D. Department of Endocrine and Otorhinolaryngic—Head & Neck Pathology (JAW, DKH, LDRT), and Department of Orthopedic Pathology (FHG), Armed Forces Institute of Pathology, Washington, DC	Mod Pathol 2001;14:1209-1215 Abstract quote True giant cell tumors of the larynx (GCTL) are quite rare, and only individual case reports are documented in the literature. Eight cases of GCTL were identified in the Otorhinolaryngic Pathology Tumor Registry between 1966 and 2000. There were 2 women and 6 men, ages 26 to 62 years (mean, 44.5 yrs). Patients presented with a palpable neck mass (n = 5), airway obstruction (n = 3), hoarseness (n = 3), and dysphagia (n = 2). All tumors involved the thyroid cartilage, a few with local extension. The mean tumor size was 4.1 cm. Histologically, the tumors showed no connection to the surface epithelium and arose in sites of ossification. The tumors had an expansile, infiltrative growth and consisted of numerous multinucleated osteoclast-like giant cells within a cellular stroma composed of plump, oval mononuclear cells. Of interest was that the nuclei of the giant cells were similar to the nuclei of the stromal cells. Treatment included biopsy only with adjuvant therapy (n = 2), local resection (n = 3), and total laryngectomy (n = 3). Follow-up showed 5 patients were alive without evidence of disease (mean follow-up, 6.9 yrs); 2 died of unrelated causes (mean survival, 22.2 yrs). No patients developed recurrences. GCTL are rare tumors that can cause significant airway obstruction. Complete surgical resection yields an excellent outcome without adjuvant therapy.
SPHENOID
Malignant giant cell tumor of the sphenoid. Chan J, Gannon FH, Thompson LD. Departments of Otolaryngology and Communicative Disorders, The Cleveland Clinic Foundation, Cleveland, OH; and the Departments of Orthopedic Pathology and Endocrine and Otorhinolaryngic-Head & Neck Pathology, Armed Forces Institute of Pathology, Washington, DC.	Ann Diagn Pathol 2003 Apr;7(2):100-105 Abstract quote Malignant giant cell tumors (MGCTs) of the sphenoid sinus are extremely rare neoplasms. They are challenging to diagnose and difficult to treat because of their skull base location. To the best of our knowledge, we report the first case of a primary MGCT of the sphenoid arising in a patient with Paget's disease. A 77-year-old man presented with epistaxis and a history of Paget's disease. There was normal cranial nerve function although radiographic images disclosed a large mass centered in the sphenoid sinus and extending into the ethmoid and maxillary sinuses. Excisional biopsy revealed a MGCT composed of a cellular stroma with increased mitotic activity and necrosis with giant cells present throughout. Additional therapy was declined and the patient died with disease 7 months later. Because of their rarity, no treatment guidelines exist for the management of MGCTs of the sphenoid. We discuss both the diagnostic and therapeutic considerations based on a review of the pertinent literature.
VERTEBRAL COLUMN
Synovial-type giant cell tumors of the vertebral column: A clinicopathologic study of 15 cases, with a review of the literature and discussion of the differential diagnosis. Furlong MA, Motamedi K, Laskin WB, Vinh TN, Murphey M, Sweet DE, Fetsch JF.	Hum Pathol. 2003 Jul;34(7):670-9 Abstract quote Synovial and tenosynovial giant cell tumors only rarely arise in close proximity to the axial skeleton; to date, fewer than 30 examples have been reported in the English-language medical literature. In this report we describe the clinical, radiologic, histopathologic, and immunohistochemical findings in 15 cases retrieved from our files. The study group comprised 7 males and 8 females, ranging in age from 17 to 44 years (mean age, 32 years). The tumors involved the cervical (n = 11), thoracic (n = 1), lumbar (n = 2), and sacrococcygeal (n = 1) regions and ranged in size from 1.0 to 6.0 cm in greatest dimension (median size, 3 cm). Symptoms were present for 2 months to at least 2 years, with the most common complaint being pain localized to the spinal region (n = 12). Ten patients also had radicular symptoms. Radiologic studies, available for 11 cases, usually demonstrated a mass involving the posterior aspect of adjoining vertebrae. Bony abnormalities (including scalloping, erosion, and destruction), facet joint and soft tissue involvement, and extradural extension were typically present. Histologically, all tumors contained a proliferation of epithelioid (histiocytoid) cells, admixed with varying numbers of osteoclast-like giant cells, siderophages, xanthoma cells, lymphocytes, and some spindled fibroblast-like cells. Only 1 tumor had the classic villiform architecture of pigmented villonodular synovitis. The remaining 14 tumors had a nodular appearance with varying amounts of collagen. Seven of these had definite histological evidence of infiltrative growth, and 6 had some features that warranted concern for possible infiltration. Only 1 tumor had findings fully compatible with a localized synovial-type giant cell tumor/nodular (teno)synovitis. All tumors had mitotic activity, with mitotic counts ranging from 1 to 21 mitotic figures per 50 high-power fields (HPFs) (mean mitotic count, 5 mitotic figures/50 HPFs). Immunohistochemistry was performed on 5 tumors, and immunoreactivity was present for CD68, CD163, and vimentin. Limited immunoreactivity for muscle actin (HUC1-1) was also noted. Follow-up information was available for 9 of the 15 patients (60%). Five patients had no evidence of recurrent or persistent disease 4 months to 9 years after undergoing either a local excision with gross total tumor removal (with or without irradiation) or a wide en bloc resection. Four patients had persistent disease after undergoing either an incomplete resection or biopsy with spinal fusion procedure. All 4 of these patients had additional surgical intervention (accompanied by irradiation in 2 instances), but only one was known to be disease-free at last follow-up (10 years after gross total tumor removal). No patient has experienced a metastasis or died of disease. The best predictor of outcome was gross total tumor removal at the surgical outset.

 

HISTOLOGICAL TYPES	CHARACTERIZATION
General	Background population of mononuclear cells with multinucleated giant cells having similar nuclear features Mitotic figures abundant, with 2 or more per hpf Giant cells may contain a hundred or more nuclei 50% of tumors contain reactive osteoid and woven bone, usually at the advancing border of the tumor Stroma is vascular, often with hemorrhage May be associated with an aneurysmal bone cyst
VARIANTS
Pseudoanaplastic giant cell tumor	Arch Pathol Lab Med 1999;123:163-166 Classic case by clinical and radiographs occurring in the sacrum of a young woman Focal anaplasia of the mononuclear cells, primarily degenerative atypia, lacking mitotic figures
Malignant Giant Cell Tumor	Pathol Case Rev 2001;6:33-37 Controversial term, Unni prefers the term "Malignancy in giant cell tumor" Unni defines it as: Sarcoma which arises in juxtaposition to a benign giant cel tumor or at the site of a previously documented giant cell tumor May be classified as primary and secondary Most malignancies are secondary His series of 34 cases: 30 were secondary 24 were post irradiation 6 occurred after surgical treatment alone 5 primary tumors

 

SPECIAL STAINS/ IMMUNO-HISTOCHEMISTRY	CHARACTERIZATION
ESTROGEN RECEPTOR
Estrogen receptor expression in giant cell tumors of the bone. Olivera P, Perez E, Ortega A, Terual R, Gomes C, Moreno LF, Duenas A, De La Garza J, Melendez-Zajgla J, Maldonado V. Laboratorio de Biologia Molecular, Division de Investigacion Basica, Instituto Nacional de Cancerologia, Mexico City, Mexico; Pathology Service and Surgical Service, Magdalena de las Salinas Hospital, IMSS, Mexico City, Mexico; and Departamento de Genetica y Biologia Molecular, Centro de Investigacion y Estudios Avanzados, IPN, Mexico City, Mexico	Hum Pathol 2002 Feb;33(2):165-169 Abstract quote Giant cell tumors (GCTs) of the bone are primary skeletal neoplasms that behave intermediately between a true benign and an overtly malignant neoplasm. For two decades, controversial reports have found estrogen receptor (ER) expression in isolated cells or small numbers of samples from these tumors. In this report, we studied by immunohistochemistry 88 cases of GCTs and found that 51% of the samples expressed ER. Furthermore, we found that a subset of seven samples analyzed for ER expression by western blot was positive. To address whether the ER expressed in these samples could be functional, isolated cells were exposed to beta-estradiol and growth curves were generated. Exposure of cells to beta-estradiol induced a small but significant growth in the cells. These results strongly support that GCTs of the bone express functional ERs.
p63
Giant cell tumor of bone express p63. Dickson BC, Li SQ, Wunder JS, Ferguson PC, Eslami B, Werier JA, Turcotte RE, Kandel RA. 1Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, ON, Canada.	Mod Pathol. 2008 Apr;21(4):369-75. Abstract quote p63 contributes to skeletal development and tumor formation; however, little is known regarding its activity in the context of bone and soft tissue neoplasms. The purpose of this study was to investigate p63 expression in giant cell tumor of bone and to determine whether it can be used to discriminate between other giant cell-rich tumors. Seventeen cases of giant cell tumor of bone were examined to determine the cell type expressing p63 and identify the isoforms present. Total RNA or cell protein was extracted from mononuclear- or giant cell-enriched fractions or intact giant cell tumor of bone and examined by RT-PCR or western blot, respectively. Immunohistochemistry was used to evaluate p63 expression in paraffin embedded sections of giant cell tumor of bone and in tumors containing multinucleated giant cells, including: giant cell tumor of tendon sheath, pigmented villonodular synovitis, aneurysmal bone cyst, chondroblastoma, and central giant cell granuloma. The mononuclear cell component in all cases of giant cell tumor of bone was found to express all forms of TAp63 (alpha, beta, and gamma), whereas only low levels of the TAp63 alpha and beta isoforms were detected in multinucleated cells; DeltaNp63 was not detected in these tumors. Western blot analysis identified p63 protein as being predominately localized to mononuclear cells compared to giant cells. This was confirmed by immunohistochemical staining of paraffin-embedded tumor sections, with expression identified in all cases of giant cell tumor of bone. Only a proportion of cases of aneurysmal bone cyst and chondroblastoma showed p63 immunoreactivity whereas it was not detected in central giant cell granuloma, giant cell tumor of tendon sheath, or pigmented villonodular synovitis. The differential expression of p63 in giant cell tumor of bone and central giant cell granuloma suggest that these two tumors may have a different pathogenesis. Moreover, p63 may be a useful biomarker to differentiate giant cell tumor of bone from central giant cell granuloma and other giant cell-rich tumors, such as giant cell tumor of tendon sheath and pigmented villonodular synovitis.

 

DIFFERENTIAL DIAGNOSIS	KEY DIFFERENTIATING FEATURES
General	In general, one should question the diagnosis of a giant cell tumor if there is: Open or uninvolved epiphysis Diffusely permeative growth pattern Reactive sclerosis Abundant matrix production
Giant cell reparative granuloma-Brown tumor
Nonossifying fibroma
Benign fibrous histiocytoma
Aneurysmal bone cyst
Osteosarcoma with prominent giant cells
Metastatic carcinoma with giant cells
INJURY
High-pressure paint-gun injury of the finger simulating giant cell tumor of tendon sheath. Stefanato CM, Turner MS, Bhawan J. Department of Dermatology, Dermatopathology Section, Boston University School of Medicine, Boston, MA, USA.	J Cutan Pathol. 2005 Feb;32(2):179-83. Abstract quote   High-pressure paint guns deliver paint at approximately 3000 pounds per square inch. At this pressure, paint will penetrate the skin and spread quickly through fascial planes and tendon sheaths. The present case is that of a lesion from the finger of a 35-year-old white male in whom a history was initially unavailable. Histologic examination revealed diffuse fibrohistiocytic proliferation and giant cells, with numerous darkly pigmented, uniformly small-sized particles throughout the lesion. The initial impression was that of a giant cell tumor of tendon sheath. However, the pigment particles were negative for Perls stain, and polariscopic examination revealed clear refractile fragments. These findings raised the possibility that the lesion was the result of a traumatic event. On further inquiry, it was revealed that the patient had sustained a high-pressure paint-gun injury 1 year earlier. The simulation, histopathologically, of a giant cell tumor of tendon sheath by a high-pressure paint-gun injury has not, to our knowledge, been reported previously, nor has the histologic finding of small, uniformly sized pigment particles and polarizable refractile fragments in this particular type of injury.
THYMOMA
Giant cell tumor of rib masquerading as thymoma: a diagnostic pitfall in needle core biopsy of the mediastinum. Volmar KE, Sporn TA, Toloza EM, Martinez S, Dodd LG, Xie HB. Department of Pathology, Duke University Medical Center, Durham, NC 27710, USA.	Arch Pathol Lab Med. 2004 Apr;128(4):452-5. Abstract quote Giant cell tumor of bone is rarely seen in the rib, where it may present as a mediastinal mass. The diagnosis of giant cell tumor of bone is generally straightforward by fine-needle aspiration or needle core biopsy, but sampling problems may lead to confusion with other neoplasms or inflammatory processes. Here, we report a case of giant cell tumor of rib presenting as a mediastinal mass in a 36-year-old man. Because of inadequate sampling and inaccurate clinical information, the tumor was initially mistaken for thymoma. When the mass failed to respond to conventional chemotherapy, additional tissue was obtained and a giant cell tumor was diagnosed. Consequently, definitive therapy was delayed. The case illustrates an important diagnostic pitfall in the biopsy of mediastinal masses.

 

PROGNOSIS AND TREATMENT	CHARACTERIZATION
PROGNOSIS	Effectiveness of original treatment is most important prognostic factor
Recurrence	60% will recur if treated by by curettage only Occurs within 2 years and almost all within 5 years
Metastasis	Recurrence after 5 years is highly suspicious for malignant transformation
Malignant giant cell tumor	Dedifferentiation of the typical tumor, arising in association with a typical giant cell tumor
Benign metastasizing giant cell tumor	1-2% of typical giant cell tumors have metastasis, almost always pulmonary, and histologically identical to the primary tumor
TREATMENT	Cryosurgery has achieved good success with 90-100% cure
	Supervoltage radiation therapy may be helpful with local control rates of 85-90% May cause a transient rapid enlargement for several weeks to months-termed Herendeen phenomenon

Macpherson and Pincus. Clinical Diagnosis and Management by Laboratory Methods. Twentyfirst Edition. WB Saunders. 2006.
Rosai J. Ackerman's Surgical Pathology. Ninth Edition. Mosby 2004.
Sternberg S. Diagnostic Surgical Pathology. Fourth Edition. Lipincott Williams and Wilkins 2004.
Robbins Pathologic Basis of Disease. Seventh Edition. WB Saunders 2005.
DeMay RM. The Art and Science of Cytopathology. Volume 1 and 2. ASCP Press. 1996.
Weedon D. Weedon's Skin Pathology Second Edition. Churchill Livingstone. 2002
Fitzpatrick's Dermatology in General Medicine. 6th Edition. McGraw-Hill. 2003.
Weiss SW and Goldblum JR. Enzinger and Weiss's Soft Tissue Tumors. Fifth Edition. Mosby Elesevier 2008

Basic Principles of Disease
Learn the basic disease classifications of cancers, infections, and inflammation

Commonly Used Terms
This is a glossary of terms often found in a pathology report.

Diagnostic Process
Learn how a pathologist makes a diagnosis using a microscope

Surgical Pathology Report
Examine an actual biopsy report to understand what each section means

Special Stains
Understand the tools the pathologist utilizes to aid in the diagnosis

How Accurate is My Report?
Pathologists actively oversee every area of the laboratory to ensure your report is accurate

Got Path?
Recent teaching cases and lectures presented in conferences

• Pathologists Who Make A Difference
• Search for a Physician Specialist
• Gross or Clinical Photo
• Microscopic Photo

Send mail to The Doctor's Doctor with questions or comments about this web site.
Read the Medical Disclaimer.

Copyright © The Doctor's Doctor