Recurrent FOXK1::GRHL and GPS2::GRHL fusions in trichogerminoma.

We report 21 cases of trichogerminoma harbouring previously undescribed FOXK1::GRHL1/2 or GPS2::GRHL1/2/3 in-frame fusion transcripts. Microscopic examination of a preliminary set of five cases revealed well-delimitated tumours located in the dermis with frequent extension to the subcutaneous tissue. Tumours presented a massive and nodular architecture and consisted of a proliferation of basaloid cells. A biphasic pattern sometime resulting in tumour cell nests ('cell balls') was present. Immunohistochemistry demonstrated the expression of cytokeratins (CKs) 15, 17, and PHLDA1. In addition, numerous CK20-positive Merkel cells were detected. RNA sequencing (RNA-seq) revealed a FOXK1::GRHL1 chimeric transcript in three cases and a FOXK1::GRHL2 fusion in two cases. In a second series for validation (n = 88), FOXK1::GRHL1/2 fusion transcripts were detected by RT-qPCR or FISH in an additional 12 trichogerminomas and not in any other follicular tumour entities or basal cell carcinoma cases (n = 66). Additional RNA-seq analysis in trichogerminoma cases without detected FOXK1::GRHL1/2 rearrangements revealed GPS2::GRHL1 fusion transcripts in two cases, GPS2::GRHL2 in one case, and GPS2::GRHL3 fusion transcript in one case. Therefore, our study strongly suggests that GRHL1/2/3 gene rearrangements might represent the oncogenic driver in trichogerminoma, a subset of follicular tumours characterized by immature features and numerous Merkel cells. © 2022 The Pathological Society of Great Britain and Ireland.

Clinical and pathological significance of cutaneous manifestations in ANCA-associated vasculitides.

OBJECTIVES: Cutaneous manifestations (CM) in ANCA-associated vasculitides (AAV) are frequent, but data on clinical significance and clinical-pathological correlations are lacking. METHODS: We conducted a multicenter, retrospective study including 1553 AAV patients. Clinical, biological and pathological features have been analyzed, and tissue samples from 46 biopsies were reviewed in a blind manner. RESULTS: CM were more frequent in EGPA (53.0%) and MPA (51.9%) than in GPA (36.7%). Lesions more frequently associated with GPA were oral ulcers (4.6% vs. 2.5% in EGPA and 0.3% in MPA), while pyoderma gangrenosum and palpebral xanthoma were specific to GPA. Lesions associated with MPA were segmentary edema (19.5% vs. 12.7% in EGPA and 4.3% in GPA) and livedo (12.4% vs. 0.5% and 2.6%, respectively), whereas those associated with EGPA were urticarial lesions (11.5% vs. 1.9% in GPA and 3.5% in MPA) and nodules (12,2% vs. 8.9% in GPA and 4.7% in MPA). In GPA, CM patients had more frequent vasculitis than granulomatous phenotype, and poorer relapse-free and overall survival. Pathological analysis showed vasculitis and/or granulomatous infiltrates in 87.5% of GPA, in 61.1% of EGPA and in all MPA. Vasculitis was more frequently observed in purpura and nodules, while granulomas were differently located and organized within vessels or interstitium according to the type of lesions. CONCLUSION: Each AAV seemed to be associated with a peculiar pattern of cutaneous lesions. CM are associated with poorer prognosis in GPA. Clinical-pathological correlations showed no specific feature of each AAV, whereas granulomatous infiltrates differ according to the type of lesions.

Syringotropic mycosis fungoides: clinical and histologic features, response to treatment, and outcome in 19 patients.

BACKGROUND: A rare variant of mycosis fungoides (MF), syringotropic MF (STMF) is characterized by a particular tropism of the lymphocytic infiltrate for the eccrine structures, and included in the follicular subtype of MF in the World Health Organization-European Organization for Research and Treatment of Cancer classification of cutaneous lymphomas. OBJECTIVE: We sought to determine the clinicopathologic features and disease course of patients with STMF. METHODS: A retrospective study was conducted to identify patients with STMF from 1998 to 2013. RESULTS: Nineteen patients were included: 15 men and 4 women, mean age 55 years (range, 24-86). Most had multiple lesions (n=16, 84%) with associated alopecia (n=12, 63%) and/or punctuated aspect (n=12, 63%). Palms or soles were involved in 10 cases (53%). Folliculotropism was found in 13 cases (68%). After a median follow-up of 70 months (range, 2-140), 3 patients died, 1 from disease-related death. The 5-year overall and disease-specific survival were 100%. The disease-specific survival was significantly higher than in 54 patients with folliculotropic MF without syringotropism (5-year disease-specific survival, 74%; 95% confidence interval, 58%-94%, P=.02). LIMITATIONS: Retrospective setting is a limitation. CONCLUSIONS: In the spectrum of adnexotropic MF, STMF appears as a distinct entity from follicular MF, with peculiar clinical characteristics and natural history.

Anogenital pseudotumoral herpes and HIV infection: a new challenge for diagnosis and treatment.

HIV-infected patients may develop rare anogenital pseudotumoral herpes potentially mimicking epidermoid carcinoma. We assessed treatment in five new cases with a median follow-up of 3.3 years. Recurrence and clinical nucleoside analog resistance were observed in all patients. All drug treatments were only temporarily curative and clinical responses varied between patients and recurrences. Foscavir seemed to be the most appropriate second-line treatment and cidofovir or thalidomide should be considered as alternative treatments.

Successful treatment of black-grain mycetoma with voriconazole.

Fungal mycetoma (or eumycetoma) are endemic diseases in tropical areas that have economic effects because of their chronic and disabling evolution. Classic treatments include surgery and antifungal drugs, but these have multiple side effects. We report a case of black-grain fungal mycetoma successfully treated with voriconazole without side effects. The duration of the treatment remains unclear, but must be prolonged because of the frequency of relapses.