Unclear Cystic Lesion of the Thumb: A Rare Case of a Mainly Cystic Digital Papillary Adenocarcinoma.

Digital papillary adenocarcinoma (DPA) is a malignant neoplasia of the eccrine glands primarily found at the fingers (A. ArsalanWerner et al. Handchirurgie, Mikrochirurgie, plastische Chirurgie 2013; 45: 287–292). It was first described by Helwig 1984 (E. B. Helwig. Journal of Cutaneous Pathology 1984: 11: 415-420). These tumors have metastatic potential (W. H. Duke et al. The American journal of surgical pathology 2000; 24: 775–784) and a high tendency to recur if not fully resected (T. Kobayashi et al. The American Journal of dermatopathology 2016; 38: 910–914). Clinically, these tumors normally present as a painless mass with no signs of inflammation and slow growth over months to years before patients seek medical attention. Imaging diagnosis of digital papillary adenocarcinomas is challenging because there are no specific imaging criteria. We present the case of a 68-year-old male with a local digital papillary adenocarcinoma of the right thumb with cystic appearance. Case Report