Tonsils

Background

The tonsils are located in the back of the throat. Although part of the lymphoid system of the body, a system that includes lymph nodes, thymus gland, and spleen, the function of the tonsil has never been quite defined. For many years, a tonsillectomy was a childhood rite of passage. Today, this procedure is done far less frequently. In fact many tonsillectomies are now done to treat sleep apnea.

OUTLINE

Pathogenesis

Special Stains/Immunohistochemistry/Electron Microscopy Tdt positive cells

Gross Appearance and Clinical Variants

Histopathological Variants

Commonly Used Terms

Internet Links

PATHOGENESIS CHARACTERIZATION

HUMAN HERPESVIRUS 6

Prevalence and Cellular Reservoir of Latent Human Herpesvirus 6 in Tonsillar Lymphoid Tissue

Karen S. Roush, MD
Rana K. Domiati-Saad, PhD
Linda R. Margraf, MD
Karen Krisher, PhD
Richard H. Scheuermann, PhD
Beverly Barton Rogers, MD
D. Brian Dawson, PhD

Am J Clin Pathol 2001;116:648-654 Abstract quote

There are few studies that examine prevalence, quantity, and cellular proclivity of latent human herpesvirus 6 (HHV-6) in healthy populations.

We examined 69 tonsils with paired blood specimens from children without evidence of acute infection. By polymerase chain reaction (PCR), HHV-6 was detected at low levels in 100% of tonsils and 39% of blood samples (n = 27), suggesting that prevalence of latent HHV-6 infection is high in children and may be underestimated by PCR analysis of blood. Although HHV-6A and HHV-6B were detected, HHV-6B predominated, being found in 97% of samples (n = 67). Tonsil sections from 7 cases were examined by in situ hybridization using 2 HHV-6 probes and immunohistochemical analysis. Using both in situ hybridization and immunohistochemical analysis, all tissues revealed marked HHV-6–specific staining in the squamous epithelium of the tonsillar crypts and rare positive lymphocytes.

We conclude that HHV-6 is present universally in tonsils of children, and tonsillar epithelium may be an important viral reservoir in latent infection.

HUMAN PAPILLOMAVIRUS

Prevalence of human papillomavirus type 16 DNA in squamous cell carcinoma of the palatine tonsil, and not the oral cavity, in young patients: a distinct clinicopathologic and molecular disease entity.

El-Mofty SK, Lu DW.

Washington University School of Medicine, St Louis, MO 63110, USA.

Am J Surg Pathol. 2003 Nov;27(11):1463-70. Abstract quote

Squamous cell carcinoma of the head and neck commonly affects patients in their sixth decade and older, particularly those with a prolonged history of alcohol and tobacco abuse. Less frequently, carcinomas occur in young individuals even in the absence of known risk factors.

The purpose of this study is to investigate a possible relationship between these tumors and human papilloma virus (HPV). Thirty-three cases of squamous cell carcinoma of the head and neck in young patients under the age of 40 years were studied: 15 oral, 11 tonsillar, and 7 laryngeal. HPV DNA was detected by polymerase chain reaction in 10 tonsillar and 2 laryngeal carcinomas and in none of the oral tumors. Of the 12 HPV-positive tumors, 11 were HPV16 and 1 was HPV31. HPV-positive tumors had a distinct nonkeratinizing basal cell morphology, they stained diffusely and strongly with p16 antibodies, had higher Ki-67 and lower p53 staining scores as compared with the conventional keratinizing HPV negative carcinomas.

It is concluded that in young patients high-risk HPV, particularly HPV16, is strongly associated with tonsillar squamous cell carcinoma and some cases of laryngeal, but not oral, tumors. The HPV-positive carcinomas have a distinct histopathologic and immunophenotypic features.

GROSS EXAMINATION CHARACTERIZATION

The adequacy of gross pathological examination of routine tonsils and adenoids in patients 21 years old and younger.

Williams MD, Brown HM.

Hum Pathol. 2003 Oct;34(10):1053-7 Abstract quote.

Most hospitals microscopically examine all routine tonsil and adenoid specimens from healthy pediatric patients with recurrent infections or obstructive sleep apnea. Concern over missing the rare unsuspected, significant diagnosis propagates this practice. Careful gross examination for asymmetry and clinical findings should obviate the need for routine microscopic examination of tonsil and adenoid specimens in patients age 21 years and younger.

A retrospective study was conducted using the SNOMED database of 4070 patients age 21 years or younger who underwent tonsillectomy and/or adenoidectomy between 1970 and July 2001 at the University of Florida. The age distribution of the study group was 0 to 5 years (52%), 6 to 12 years (37%), and 13 to 21 years (11%). Specimens consisted of tonsils only (15%), tonsils and adenoids (40%), and adenoids only (45%). Clinically significant diagnoses were diagnoses that impacted the care of patients and included malignancies and some infections. Non-clinically significant diagnoses included normal, acute or chronic tonsillitis, and tonsillar hyperplasia. Clinically significant pathological processes were seen in the tonsil or adenoid specimens of 3 of the 4070 patients. These 3 cases included a 2-year-old male with Burkitt's lymphoma, a 19-year-old male with non-Hodgkin's lymphoma (small noncleaved cell, non-Burkitt's type), and an 11-year-old male with a probable viral process but in whom a lymphoma could not be absolutely excluded. All 3 of these patients had signs and symptoms, including significant cervical lymphadenopathy, meriting microscopic analysis of the specimens. In conclusion, microscopic examination of all routine tonsils and adenoids for individuals 21 years or younger is not indicated.

Gross examination is still recommended. Clinical suspicion and specimen asymmetry should be used to determine when thorough histological examination is merited.

HISTOPATHOLOGY CHARACTERIZATION

VARIANTS

Histological features in routine tonsillectomy specimens: the presence and the proportion of mesenchymal tissues and seromucinous glands.

Erkilic S, Aydin A, Kocer NE.

Department of Pathology, Faculty of Medicine, Gaziantep University, Gaziantep, Turkey.
J Laryngol Otol 2002 Nov;116(11):911-3 Abstract quote
Tonsillectomy is a frequently performed operation but there is little information about the histological features of a tonsillectomy specimen.

In this study, we re-evaluated archival materials of 1220 cases who underwent tonsillectomy because of hyperplastic tonsils. Haematoxylin and eosin sections of the cases were re-examined and the presence and the proportion of mesenchymal tissues (skeletal muscle, cartilage, fat, bone) and seromucinous glands were noted as focal, multifocal or abundant.

The incidence of skeletal muscle was 89 per cent (1085 cases; 206 focal, 465 multifocal, 414 abundant), seromucinous glands 35 per cent (429 cases; 236 focal, 134 multifocal, 59 abundant), fat 21 per cent (251 cases; 208 focal, 43 multifocal), cartilage three per cent (31 cases), and bone one per cent (seven cases). Also in 165 cases (14 per cent) skeletal muscle, in 12 cases (one per cent) was seromucinous glands, in eight cases (one per cent) was cartilage, in seven cases (one per cent) fat, and in four cases (less than one per cent) bone were found between hyperplastic lymphoid tissue.

It can be concluded that mesenchymal tissues (skeletal muscle, cartilage, fat, bone) and seromucinous glands may be seen in different proportions in routine tonsillectomy specimens.

Skeletal muscle in routine tonsillectomy specimens: a common finding.

Gnepp DR, Souther J.

Department of Pathology, Brown University School of Medicine, Rhode Island Hospital, Providence 02903, USA.
Hum Pathol 2000 Jul;31(7):813-6 Abstract quote
Over the past 10 years, 1 of the authors (D.G.) has been consulted about several medical legal cases involving complications allegedly related to excessive surgery as documented by finding skeletal muscle in tonsillectomy specimens. A review of the literature showed little information about the incidence of skeletal muscle in routine tonsillectomy specimens; therefore, this study was undertaken.

Thirty sequential tonsillectomy specimens from patients with histories of hyperplastic tonsils (10 males, 20 females; ages 5, 17 to 39; mean age, 24.3 years) were processed routinely (1 section/tonsil), and evaluated on a retrospective basis using routine light microscopy (group 1). In addition, 20 sequential tonsillectomy specimens were processed in a prospective fashion, excluding sleep apnea specimens (5 males, 15 females; ages 12 to 59 years; mean age, 28.9 years) (group 2). All specimens in the first group had lymphoid hyperplasia; 25 of the 30 (83%) had skeletal muscle in soft tissue adjacent to the lymphoid elements, 20 (67%) had seromucinous glands, and in 1 there was a focus of cartilage.

In group 2, 18 had lymphoid hyperplasia and 2 contained carcinomas; 19 of 20 contained skeletal muscle ranging from a single fiber to abundant, multifocal areas with muscle, 16 (80%) had seromucinous glands, and 4 contained areas with cartilage. Additional tissue from the specimen without muscle and the tonsil with a single fiber was processed, and abundant skeletal muscle was identified in each. One may conclude that skeletal muscle is very frequently found in routine tonsillectomy specimens and, by itself, is not an indication of inappropriate surgical technique.

SPECIAL STAINS/IMMUNOPEROXIDASE/
OTHER CHARACTERIZATION

SPECIAL STAINS

IMMUNOPEROXIDASE

TdT POSITIVE CELLS

Terminal Deoxynucleotidyl Transferase–Positive Cells in Human Tonsils

James A. Strauchen, MD, and Lorraine K. Miller, PhD

Am J Clin Pathol 2001;116:12-16 Abstract quote

To study the possible cellular origin of recently recognized indolent terminal deoxynucleotidyl transferase (TdT)-positive T-lymphoblastic proliferations of the tonsils and oropharynx, we studied normal human tonsils for the presence of TdT-positive cells. TdT-positive cells were readily demonstrated in the tonsils from 15 children and adults by immunohistochemical staining. TdT-positive cells were distributed in discrete foci at the periphery of lobules of lymphoid tissue and adjacent to fibrous septa and had the morphologic features of small to medium-sized lymphocytes. Double-antibody staining indicated the TdT-positive cells had the phenotype of uncommitted early lymphoid precursors (CD3–, CD79a–, CD10–). Foci of TdT-positive cells were not identified in 6 reactive lymph nodes studied as controls. These studies indicate that tonsils, like bone marrow and thymus, are sites of lymphopoiesis.

The presence of TdT-positive precursor cells in human tonsils may be a factor in the pathogenesis of recently described indolent T-lymphoblastic proliferations involving the tonsils and oropharynx. The presence of TdT-positive cells in human tonsils should not be misinterpreted as evidence of lymphoblastic lymphoma or leukemia.

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.

Commonly Used Terms

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

Internet Links

Last Updated 11/17/2003

HISTOPATHOLOGY	CHARACTERIZATION
VARIANTS
Histological features in routine tonsillectomy specimens: the presence and the proportion of mesenchymal tissues and seromucinous glands. Erkilic S, Aydin A, Kocer NE. Department of Pathology, Faculty of Medicine, Gaziantep University, Gaziantep, Turkey.	J Laryngol Otol 2002 Nov;116(11):911-3 Abstract quote Tonsillectomy is a frequently performed operation but there is little information about the histological features of a tonsillectomy specimen. In this study, we re-evaluated archival materials of 1220 cases who underwent tonsillectomy because of hyperplastic tonsils. Haematoxylin and eosin sections of the cases were re-examined and the presence and the proportion of mesenchymal tissues (skeletal muscle, cartilage, fat, bone) and seromucinous glands were noted as focal, multifocal or abundant. The incidence of skeletal muscle was 89 per cent (1085 cases; 206 focal, 465 multifocal, 414 abundant), seromucinous glands 35 per cent (429 cases; 236 focal, 134 multifocal, 59 abundant), fat 21 per cent (251 cases; 208 focal, 43 multifocal), cartilage three per cent (31 cases), and bone one per cent (seven cases). Also in 165 cases (14 per cent) skeletal muscle, in 12 cases (one per cent) was seromucinous glands, in eight cases (one per cent) was cartilage, in seven cases (one per cent) fat, and in four cases (less than one per cent) bone were found between hyperplastic lymphoid tissue. It can be concluded that mesenchymal tissues (skeletal muscle, cartilage, fat, bone) and seromucinous glands may be seen in different proportions in routine tonsillectomy specimens.
Skeletal muscle in routine tonsillectomy specimens: a common finding. Gnepp DR, Souther J. Department of Pathology, Brown University School of Medicine, Rhode Island Hospital, Providence 02903, USA.	Hum Pathol 2000 Jul;31(7):813-6 Abstract quote Over the past 10 years, 1 of the authors (D.G.) has been consulted about several medical legal cases involving complications allegedly related to excessive surgery as documented by finding skeletal muscle in tonsillectomy specimens. A review of the literature showed little information about the incidence of skeletal muscle in routine tonsillectomy specimens; therefore, this study was undertaken. Thirty sequential tonsillectomy specimens from patients with histories of hyperplastic tonsils (10 males, 20 females; ages 5, 17 to 39; mean age, 24.3 years) were processed routinely (1 section/tonsil), and evaluated on a retrospective basis using routine light microscopy (group 1). In addition, 20 sequential tonsillectomy specimens were processed in a prospective fashion, excluding sleep apnea specimens (5 males, 15 females; ages 12 to 59 years; mean age, 28.9 years) (group 2). All specimens in the first group had lymphoid hyperplasia; 25 of the 30 (83%) had skeletal muscle in soft tissue adjacent to the lymphoid elements, 20 (67%) had seromucinous glands, and in 1 there was a focus of cartilage. In group 2, 18 had lymphoid hyperplasia and 2 contained carcinomas; 19 of 20 contained skeletal muscle ranging from a single fiber to abundant, multifocal areas with muscle, 16 (80%) had seromucinous glands, and 4 contained areas with cartilage. Additional tissue from the specimen without muscle and the tonsil with a single fiber was processed, and abundant skeletal muscle was identified in each. One may conclude that skeletal muscle is very frequently found in routine tonsillectomy specimens and, by itself, is not an indication of inappropriate surgical technique.

Pathogenesis
Special Stains/Immunohistochemistry/Electron Microscopy	Tdt positive cells
Gross Appearance and Clinical Variants
Histopathological Variants
Commonly Used Terms
Internet Links

SPECIAL STAINS/IMMUNOPEROXIDASE/ OTHER	CHARACTERIZATION
SPECIAL STAINS
IMMUNOPEROXIDASE
TdT POSITIVE CELLS
Terminal Deoxynucleotidyl Transferase–Positive Cells in Human Tonsils James A. Strauchen, MD, and Lorraine K. Miller, PhD	Am J Clin Pathol 2001;116:12-16 Abstract quote To study the possible cellular origin of recently recognized indolent terminal deoxynucleotidyl transferase (TdT)-positive T-lymphoblastic proliferations of the tonsils and oropharynx, we studied normal human tonsils for the presence of TdT-positive cells. TdT-positive cells were readily demonstrated in the tonsils from 15 children and adults by immunohistochemical staining. TdT-positive cells were distributed in discrete foci at the periphery of lobules of lymphoid tissue and adjacent to fibrous septa and had the morphologic features of small to medium-sized lymphocytes. Double-antibody staining indicated the TdT-positive cells had the phenotype of uncommitted early lymphoid precursors (CD3–, CD79a–, CD10–). Foci of TdT-positive cells were not identified in 6 reactive lymph nodes studied as controls. These studies indicate that tonsils, like bone marrow and thymus, are sites of lymphopoiesis. The presence of TdT-positive precursor cells in human tonsils may be a factor in the pathogenesis of recently described indolent T-lymphoblastic proliferations involving the tonsils and oropharynx. The presence of TdT-positive cells in human tonsils should not be misinterpreted as evidence of lymphoblastic lymphoma or leukemia.