Histopathologic Spectrum of Primary Cutaneous T-Cell Lymphomas: Insights From a Vietnamese Case Series.

[BACKGROUND] Primary cutaneous T-cell lymphomas (PCTCLs) are a rare and heterogeneous group of extranodal non-Hodgkin lymphomas originating from skin-homing T cells. Most current knowledge about PCTCLs is derived from Western populations, with limited data available from Southeast Asia, including Vietnam.

[OBJECTIVE] To characterize the clinical, histopathologic, and immunohistochemical features of PCTCLs in a cohort of Vietnamese patients.

[MATERIALS AND METHODS] A retrospective case series was conducted involving 39 PCTCL cases. Demographic and clinical data were collected from medical records and archived clinical images. Histopathologic and immunohistochemical evaluations were independently performed by 3 pathologists, following the fifth edition of the WHO Classification of Haematolymphoid Tumours.

[RESULTS] Subcutaneous panniculitis-like T-cell lymphoma was most frequent (36%), followed by mycosis fungoides (MF, 28%) and primary cutaneous anaplastic large cell lymphoma (pcALCL, 15%). Subcutaneous panniculitis-like T-cell lymphoma predominantly affected young women, whereas MF and pcALCL occurred in older adults (median age, 64 years). Beyond canonical clinicopathologic features, notable findings included high rates of Pautrier microabscesses and eosinophilic infiltration in MF (each 73%), 1 ulcerated MF case, and 1 pcALCL with a CD4-/CD8- phenotype.

[CONCLUSIONS] Although clinicopathologic features largely aligned with established diagnostic criteria, several differences from international series were observed. These disparities likely reflect delayed diagnosis, referral bias toward more severe disease, and broader systemic and cultural factors in Vietnam, and constrained availability of advanced diagnostic assays, underscoring the need to strengthen clinicopathologic integration and expand access to specialized care.