Background

Calcifying fibrous pseudotumor (CFT) is a rare benign soft tissue lesion composed of dense hyalinized fibrous tissue containing bland spindle-shaped cells admixed with a lymphoplasmacytic infiltrate and foci of dystrophic and often psammomatous calcifications. These tumors most commonly occur in the extremities, trunk, inguinal and scrotal regions, and head and neck.

OUTLINE

Epidemiology
Pathogenesis
Gross Appearance and Clinical Variants
Histopathological Features and Variants
Prognosis
Treatment
Commonly Used Terms
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EPIDEMIOLOGY	CHARACTERIZATION
SYNONYMS	Childhood fibrous pseudotumor with psammoma bodies
INCIDENCE	Rare, less than 30 reported cases in the literature
AGE RANGE-MEDIAN	2-3rd decades
SEX (M:F)	Slight Female
FAMILIAL
Familial Peritoneal Multifocal Calcifying Fibrous Tumor Karl T.K. Chen, MD	Am J Clin Pathol 2003;119:811-815 Abstract quote Calcifying fibrous tumor (CFT) is usually solitary, involving the soft tissue, pleura, or peritoneum. The cause and pathogenesis are unclear. Cases with multifocal lesions are rare, and a familial occurrence has not been reported. Herein, a family in which 2 sisters developed multifocal peritoneal CFT is described. The sisters each had abdominal pain, and each was found at laparotomy to have multiple nodular lesions on the mesenteric, omental, and small bowel serosal surfaces. Many lesions were composed of collagenous, paucicellular, fibrous tissue with psammomatous or dystrophic calcification, consistent with CFT. Some lesions were composed of more cellular spindle-celled tissue resembling inflammatory myofibroblastic tumors. Both patients were alive and well 19 and 17 years after diagnosis, respectively. One other sibling and 2 children of one of the sisters were speculated to have the same disorder, based on clinical findings. This report suggests that there may be a genetic susceptibility to CFT, although chance and common environmental etiologic factors cannot be excluded.

 

PATHOGENESIS	CHARACTERIZATION
Immunohistochemical analysis of anaplastic lymphoma kinase expression in deep soft tissue calcifying fibrous pseudotumor: Evidence of a late sclerosing stage of inflammatory myofibroblastic tumor?	Ann Diagn Pathol 2001;5:10-14 Case Series: Seven cases of deep soft tissue CFT diagnosed at the Cleveland Clinic Foundation and the University of Florida with available paraffin-embedded blocks using a monoclonal antibody to ALK (Dako, Carpenteria, CA) and a modified avidin-biotin complex method. The cohort included six women and one man with a median age at diagnosis of 43 years (range, 26 to 67 years). Sites of CFT included mesentery (3), peritoneum (1), omentum (1), serosa of small bowel (1), and anterior mediastinum (1). Immunohistochemically, only one case showed focal staining for ALK. The remaining six cases were negative, with appropriate positive and negative control staining Conclusion: Unlike IMT, CFT in deep soft tissue locations rarely expresses ALK by immunohistochemistry, suggesting that CFT is a different clinicopathologic entity than IMT, as opposed to representing a “burned out” IMT.
Calcifying Fibrous Pseudotumor versus Inflammatory Myofibroblastic Tumor: A Histological and Immunohistochemical Comparison Kalisha A. Hill, M.D., Frank Gonzalez-Crussi, M.D. and Pauline M. Chou, M.D. Department of Surgical PathologyChildren’s Memorial Hospital, Northwestern University, Chicago, Illinois	Mod Pathol 2001;14:784-790 Abstract quote Calcifying fibrous pseudotumor (CFP), a recently described lesion, is characterized by a predominantly lymphoplasmacytic infiltrate with abundant hyalinized collagen and psammomatous or dystrophic calcifications. The cause and pathogenesis are unclear, but it has been postulated that CFP may represent a sclerosing end stage of inflammatory myofibroblastic tumor (IMT). We compared the histological and immunohistochemical profiles of seven cases diagnosed as CFP and seven as IMT. Histologically, the CFP demonstrated varying degrees of calcifications in addition to fibroblastic proliferation admixed with inflammatory cells composed of lymphocytes, eosinophils, and mast cells. The IMTs rarely contain calcifications and had a myofibroblastic proliferation varying from hyalinized acellular collagen to florid fibroblastic proliferations simulating sarcoma. The inflammatory component was composed primarily of plasma cells and lymphocytes, sometimes arranged as lymphoid aggregates with germinal centers. All CFP cases were diffusely positive for factor XIIIa and negative for smooth muscle actin, muscle-specific actin, and CD34. All IMTs demonstrated diffuse positivity for actin, variable positivity for CD34, and focal positivity for Factor XIIIa. This study demonstrates certain distinct histologic, immunohistochemical, and electron microscopic features between IMTs and CFPs.

 

GROSS APPEARANCE/CLINICAL VARIANTS	CHARACTERIZATION
General	Majority between 3-5 cm
VARIANTS
Pleura	Am J Clin Pathol 1996;105:189-194
Mediastinum
Visceral peritoneum

 

HISTOLOGICAL TYPES	CHARACTERIZATION
General	Densely hyalinized collagen with cytologically bland spindle cells Variable lymphoplasmacytic infiltrate Dystrophic or psammomatous calcifications

 

PROGNOSIS AND TREATMENT	CHARACTERIZATION
Prognostic Factors
Survival	Benign
Recurrence	Am J Surg Pathol 1993;17:502-508 One case of local recurrence after 7.5 years after initial surgical excision
Metastasis
Treatment	Complete surgical removal

Am J Surg Pathol 1993;17:502-508
Henry JB. Clinical Diagnosis and Management by Laboratory Methods. Twentieth Edition. WB Saunders. 2001.
Rosai J. Ackerman's Surgical Pathology. Eight Edition. Mosby 1996.
Sternberg S. Diagnostic Surgical Pathology. Third Edition. Lipincott Williams and Wilkins 1999.
Robbins Pathologic Basis of Disease. Sixth Edition. WB Saunders 1999.
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. 5th Edition. McGraw-Hill. 1999.
Weiss SW and Goldblum JR. Enzinger and Weiss's Soft Tissue Tumors. Fourth Edition. Mosby 2001.

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Last Updated 5/25/2003

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