HIV-related parotid lymphoepithelial cysts. Immunohistochemistry and 3-D reconstruction of surgical and autopsy material with special reference to formal pathogenesis

Head and Neck Lymphomas in HIV Patients: a Clinical Perspective

Introduction  Because of the many HIV-related malignancies, the diagnosis and treatment of lymphoma in patients infected with human immunodeficiency virus are challenging. Objective  Here, we review current knowledge of the pathogenesis, epidemiology, symptomatology, diagnosis, and treatment of head and neck lymphomas in HIV patients from a clinical perspective. Data Synthesis  Although Hodgkin's lymphoma is not an AIDS-defining neoplasm, its prevalence is ten times higher in HIV patients than in the general population. NHL is the second most common malignancy in HIV patients, after Kaposi's sarcoma. In this group of patients, NHL is characterized by rapid progression, frequent extranodal involvement, and a poor outcome. HIV-related salivary gland disease is a benign condition that shares some features with lymphomas and is considered in their differential diagnosis. Conclusion  The otolaryngologist may be the first clinician to diagnose head and neck lymphomas. The increasing survival of HIV patients implies clinical and epidemiological changes in the behavior of this disease. Early diagnosis is important to improve the prognosis and avoid the propagation of HIV infection.

Cystic lymphoid hyperplasia of the parotid gland as the initial manifestation of HIV infection

We report the case of a patient who presented with cystic lymphoid hyperplasia of the right parotid gland as the index diagnosis of HIV infection. Histological examination of the excised parotid gland revealed a solid-cystic lymphoepithelial lesion with a non-keratinous squamous epithelium, which grew into the lymphoid component via anastomosing cords and islands. These anastomosing cords and islands contained variably abundant B cells, several subepithelial multinucleated histiocytes, salivary ducts infiltrated by small lymphocytes, and a dense lymphoid infiltrate containing lymphoid follicles with enlarged, irregular germinal centres.

IgG4-related disease in the head and neck

Lymphoid infiltrates are relatively common in the ocular adnexa and the salivary glands. They are of a variety of types and include both reactive processes and lymphomas. Within the ocular adnexa in years past, lymphoid proliferations were classified as inflammatory pseudotumor, reactive lymphoid hyperplasia, atypical lymphoid hyperplasia, and lymphoma. With improvements in diagnostic techniques and with advances in lymphoma subclassification, it became clear that many of the dense lymphoid infiltrates, including cases classified as lymphoma and likely some classified as atypical lymphoid hyperplasia, represented low-grade B-cell lymphomas, the most common of which by far were extranodal marginal zone lymphomas of mucosa-associated lymphoid tissue (MALT) lymphomas. Ocular adnexal inflammatory pseudotumor, reactive lymphoid hyperplasia, and chronic sclerosing sialadenitis were recognized, but the focus in diagnosis had been on avoiding misdiagnosis as a neoplastic process and in planning appropriate therapy. Recently, it has become clear that many cases of these reactive processes fall into the spectrum of immunoglobulin G4 (IgG4)-related disease, offering new insight into the pathogenesis of inflammatory lesions occurring in the ocular adnexa and the salivary glands. The majority of entities previously classified as chronic sclerosing sialadenitis, Mikulicz disease, orbital pseudolymphoma, and eosinophilic angiocentric fibrosis are now considered a part of the IgG4-related disease spectrum. In this review, we discuss the histologic and immunohistochemical features of IgG4-related disease of the head and neck and provide guidance for distinguishing this disease from its many mimics.

Selected topics on lymphoid lesions in the head and neck regions

Lymphoid tissue located in the head and neck region include multiple regional lymph node chains as well as mucosa associated lymphoid tissue of the conjunctiva, buccal and nasopharyngeal cavities (Waldeyer's ring), and thyroid and salivary glands. This region is a rich source of antigenic stimuli including infectious agents coming from the outside environment. Many reactive conditions that affect lymphoid tissue in this region may mimic neoplasia. In fact, distinguishing between benign and malignant lymphoid proliferations in the head and neck region is a relatively frequent diagnostic challenge and in many instances, this distinction is not straightforward. It therefore behooves the practicing pathologist to be able to recognize the benign lymphoproliferative disorders that affect this region so as to effectively guide the appropriate clinical management of such patients. Kimura disease, Epstein Barr lymphadenitis, HIV associated salivary gland disease and chronic sialadenitis are benign conditions that not infrequently affect lymphoid tissue in the head and neck region and that share certain overlapping features with malignant lymphoma. In this brief review, we discuss these conditions and highlight clinicopathological features that may help distinguish them from neoplastic lymphoproliferations that may share similar features.

Cystic lymphoid hyperplasia of the parotid gland in HIV-positive and HIV-negative patients: quantitative immunopathology

BACKGROUND

Benign lymphoepithelial lesions of the parotid include a spectrum of disorders ranging from lymphoepithelial sialadenitis (LESA) of Sjögren syndrome to lymphoepithelial cysts (LEC) and both human immunodeficiency virus (HIV)-related and -unrelated cystic lymphoid hyperplasia (CLH). They share a common microscopic appearance characterized by epimyoepithelial islands and/or epithelial lined cysts in a lymphoid stroma. However, they differ greatly regarding their etiology, clinical presentation, and management.

OBJECTIVE

The purpose of this study was to establish specific immunophenotypic profiles for these diverse disease entities.

STUDY DESIGN

Four cases of HIV+ CLH, 5 cases of HIV- CLH, 3 cases of LESA of Sjögren syndrome, and 3 cases of sporadic LEC were quantitatively analyzed for distribution of lymphoreticular cell subpopulations, using antibodies against CD20, CD45RO, CD4, CD8, CD57, and CD68.

RESULTS

The cystic lesions in both the HIV+ and HIV- cases were microscopically analogous. However, a marked decrease in the interfollicular CD4:CD8 ratio was observed in all HIV+ CLH cases, which was statistically significant when compared with the HIV- cases (P = .02) and cases of LESA of Sjögren syndrome (P = .03). No significant differences regarding the distribution of CD20+ B lymphocytes in epithelial cyst lining or the interfollicular or follicular distribution of CD20+, CD45RO+, CD57+, and CD68+ cells were present among the different groups.

CONCLUSION

Analysis of the interfollicular CD4:CD8 ratio may offer a simple immunophenotypic approach in the distinction of HIV+ from other lymphoepithelial lesions of the parotid gland, when HIV status is unknown and p24 immunohistochemistry is not readily available.

Submandibular and sublingual glands involvement in advanced acquired immunodeficiency syndrome (AIDS): an autopsy-based study

OBJECTIVE

To assess the histopathological, immunohistochemical (IHC), and in situ hybridization (ISH) features found in the submandibular (SM) and sublingual (SL) glands of 105 acquired immunodeficiency syndrome (AIDS) patients at autopsy.

STUDY DESIGN

Gender, age, CD4 cell level, and clinical histories were obtained from clinical charts (SM: n = 103; SL: n = 92). Histologic analysis of hematoxylin and eosin, Gomori-Grocott, and Ziehl-Neelsen stained tissues, IHC to detect infectious agents and characterize inflammatory cells in sialadenitis, and ISH for EBER-1/2 were performed.

RESULTS

The mean age of the patients and CD4 cell count were 36 years and 76 cells/microL, respectively. Fifty-eight cases (SM: n = 51 [49%]; SL: n = 54 [59%]) were considered to be microscopically normal. The most common infectious conditions were mycobacteriosis (SM: n = 11 [10%]; SL: n = 7 [7%]), followed by cytomegalovirus (CMV) (SM: n = 14 [13%]; SL: n = 2 [2%]), and cryptococcosis (SM: n = 3 [3%]; SL: n = 4 [4%]). Human immunodeficiency virus (HIV) p24 (SM: n = 2 [2%]; SL: n = 1 [1%]) and EBER-1/2 (SM: n = 9 [39%]; SL: n = 4 [20%]) were seen only in macrophages and lymphocytes, respectively. The most prevalent cells seen in chronic nonspecific sialadenitis (SM: n = 25; SL: n = 25) were CD8+ T lymphocytes, whereas CD68+ macrophages were predominant in the mycobacteriosis-associated granulomatous and nonspecific diffuse macrophagic sialadenitis. Concomitant infections occurred in 5 cases (SM: n = 4; SL: n = 1) and non-Hodgkin lymphoma in 1 case.

CONCLUSIONS

Infectious diseases and chronic nonspecific sialadenitis were the main alterations found in the SM and SL glands. These alterations were greater in the SM than in the SL glands. CD8+ T lymphocytes and CD68+ macrophages might be relevant to the pathogenesis of the sialadenitis. Clinicians should consider these diseases when assessing the major salivary glands in advanced AIDS patients and follow biosafety procedures to avoid contamination by HIV, CMV, mycobacteriosis, and cryptococcosis.

Regeneration in chronic sialadenitis: an analysis of proliferation and apoptosis based on double immunohistochemical labelling

The understanding of regeneration in salivary glands as a finely tuned balance of cellular proliferation, differentiation and apoptosis has been limited by the difficulty of identifying proliferating cells. This has been overcome in the present investigation by double immunohistochemical labelling for the proliferation-associated antigen Ki67 and for different cell-type-specific antigens applied to 8 specimens of normal parotids and 16 specimens of chronic parotid sialadenitis with particular reference to acini and intercalated ducts. In comparison with low baseline rates of proliferation in normal parotids, proliferative indices were significantly increased in chronic sialadenitis in mature acinar cells, intercalated ductal cells and myoepithelial cells without evidence of proliferation by an additional population of cells. In accordance with findings in glands of experimental animals, the present data do not support the previously postulated concept of regeneration of acini and intercalated ducts by a hypothetical population of uncommitted ductal stem cells. The demonstration of a profound capacity for intrinsic glandular regeneration from differentiated cells represents a biological basis for the good results obtained from conservative therapy of chronic sialadenitis and offers hope for novel therapies designed to reconstitute impaired salivary flow.