Benign-Appearing Palmar Lesion in a Young Woman: The Importance of Considering Digital Papillary Adenocarcinoma.

Adnexal tumors are rare skin tumors, representing less than one percent of cutaneous cancers, with diagnosis and management remaining complex due to the absence of a consensual clinical, histological, and prognostic classification.  Among them, digital papillary adenocarcinoma is an exceptional malignant eccrine tumor responsible for local recurrences and metastatic dissemination. Its clinical presentation is nonspecific, which can lead to diagnostic delays. Classically described in middle-aged men and localized on the fingers, it can nevertheless present under misleading clinical and topographical forms. We report the atypical case of a 22-year-old female patient who, since childhood, had a painless palmar lesion that later became sensitive and was initially interpreted as a benign lesion. The diagnosis was only made after excision and histological confirmation following a review by the national Rare Cancers in Dermatology network (CARADERM). Management involved surgical re-excision with exhaustive analysis of margins using the Slow-Mohs technique combined with sentinel lymph node biopsy, without evidence of residual tumor. After a prolonged follow-up of 79 months, no local or distant recurrence was observed. This case highlights the importance for hand surgeons to be aware of this type of tumor and for pathologists to rely on a double review by the national network in cases of clinico-pathological doubt to optimize diagnosis and management.