Metachronous Presentation of Digital Papillary Adenocarcinoma With Regional Lymph Node Metastasis: Two Separate Primaries or Contralateral Metastatic Disease?

Digital papillary adenocarcinoma (DPA) is a rare, potentially aggressive adnexal neoplasm arising from eccrine glands, with an incidence of approximately 0.08-0.11 per million person-years. Characteristically, DPA presents as a solitary nodule with predilection for the digits of the hands and feet. To our knowledge, the occurrence of 2 independent primary DPAs in the same patient has never been described. We present the first reported case of DPA with regional lymph node metastases and a subsequent contralateral digit lesion, raising the diagnostic question of whether the second lesion represents a second primary tumor or contralateral metastatic disease. Next generation sequencing confirmed that both tumors are HPV42 positive, providing insight into their pathogenesis. This case expands the known clinical spectrum of DPA by establishing that multiple primary tumors can arise in a single patient and may have implications for surveillance strategies in affected patients.