IgG4-related disease (IgG4-RD) is a systemic fibroinflammatory disease characterised by dense lymphoplasmacytic infiltration rich in IgG4-positive plasma cells, storiform fibrosis and obliterative phlebitis. Serum IgG4 levels are typically elevated but half of the patients had normal serum IgG4 levels. IgG4-RD represents a spectrum of diseases that involve various organs such as the pancreas, liver, kidneys, and salivary glands often manifesting as diffuse organ enlargement or a mass-like lesion mimicking cancer. An increased incidence of malignancy among patients with IgG4-RD has been reported. Thus, differentiating malignancy from IgG4-RD manifestation is important as the treatment differs. Glucocorticoids are considered first-line therapy and should be started early to prevent fibrosis. Patients usually have an excellent clinical response to steroids, and poor steroid response is indicative of an alternative diagnoses such as malignancy. This case report describes a case of IgG4-RD with renal mass in a young man that resolved with glucocorticoid therapy alone.
Plasmablastic lymphoma (PBL) is a rare aggressive subtype of mature large B cell lymphoma involving almost exclusively the extranodal regions particularly the oral cavity, frequently described in immunocompromised patients. PBL is characterized histologically by diffuse proliferation of large neoplastic cells resembling B immunoblasts or plasmablasts. The diagnosis of PBL can be difficult due to its ambiguous histopathological features mimicking most large cell lymphomas and lacking a distinctive immunophenotypic pattern. They typically lack expression of CD20 and CD79a but may express plasma cell marker, CD138. Aberrant immunoexpression of CD3, a T-cell marker in PBL in the absence of other B-cell markers is exceptionally rare, may potentially lead to incorrect interpretation. Herein, we report a case series of CD3-positive PBL of oral cavity in two individuals, which were initially misdiagnosed as high-grade T-cell lymphomas including extranodal NK/T-cell lymphoma, nasal type. Useful distinguishing clinical settings, histomorphological features, immunohistochemistry and molecular expression profiles of PBL are discussed.
Three patients presenting with parotid, submandibular, and/or lymph node masses were subjected to fine-needle aspiration cytology. Smears showed dissociated and clustered endothelial cells, eosinophils, lymphocytes, and Warthin Finkeldey giant cells. In two cases a diagnosis of Kimura's disease was suggested from the FNA cytologic smears. In the third case the presence of mononucleate cells with prominent nucleoli led to a suspicion of Hodgkin's disease. Excision biopsy and histopathologic study established a diagnosis of Kimura's disease in all three cases.
Twelve pleomorphic adenomas of minor salivary gland origin were examined for the distribution of S-100 protein, detected using the peroxidase-antiperoxidase (PAP) method. Strong S-100 protein immunoreactivity was noted in areas containing plasmacytoid cells, stellate and spindle cells against a myxochondroid or hyalinous stroma, and solid epithelial areas. Tubular and duct-like structures showed variable stainability. Stromal tissue and normal salivary glands were generally negative for S-100 protein. These findings were compared with those reported elsewhere.