Syringocystadenoma Papilliferum of the Anogenital Area and Buttocks: A Report of 16 Cases, Including Human Papillomavirus Analysis and HRAS and BRAF V600 Mutation Studies.

Syringocystadenoma papilliferum (SCAP) is a benign tumor most commonly located on the head and neck area often associated with nevus sebaceus. In its usual location, the human papillomavirus (HPV) DNA and mutations in the RAS/mitogen-activated protein kinase signaling pathway have been detected in SCAP. We studied 16 cases of SCAP in the anogenital areas and buttock where this neoplasm is rare and attempted to find out whether SCAP in these sites have different histopathological and molecular biological features. It seems that there is no significant difference between the morphology of anogenital SCAP and SCAP in other locations. Several tumors in our cohort demonstrated features resembling those seen in warts, but HPV DNA was not found in these lesions. On the contrary, we identified DNA of HPV high-risk types in some tumors without HPV-related morphology. Our study confirms the role of HRAS and BRAF V600 mutations in the pathogenesis of SCAP, including SCAP in the anogenital areas and buttock.

Plasma cell granuloma of the oral cavity: a mucosal manifestation of immunoglobulin G4-related disease or a mimic?

The aim of the study was to test the hypothesis that oral plasma cell granuloma may represent a mucosal manifestation of immunoglobulin (Ig)G4-related disease (IgG4-RD) in the oral cavity. The study sample comprised two males and four females, aged 54-79 years (median 62 years). The lesions were localized on gingival/alveolar mucosa (four cases), hard palate, and floor of the mouth, measuring 17-40 mm (median 31 mm). The duration of the lesions ranged from 3 months to several years. Information on IgG4 serum levels was available for two patients, and these were increased to 1.85 and 1.65 g/L, respectively. The follow-up period ranged 11-30 months (median 13 months). None of the lesions recurred, and none of the patients developed any manifestation of IgG4-RD. Microscopically, all cases presented as nodular lesions composed of numerous polyclonal plasma cells admixed with lymphocytes, histiocytes, mast cells, and eosinophils, set within collagenized stroma in variable proportions. Obliterative phlebitis was observed in two cases. The number of IgG4-positive plasma cells ranged between 51 and 142 per HPF (median 114), while the IgG4/IgG ratio values ranged between 0.16 and 0.72 (median 0.44) and were above 0.40 in three cases. Based on international criteria, two cases were diagnosed as definite and one as probable IgG4-RD. Oral plasma cell granuloma is a heterogeneous group of lesions, and a subset may represent a mucosal manifestation of IgG4-RD in the oral cavity.