Introduction
Digital papillary adenocarcinoma (DPA) is a rare tumour of sweat gland origin, usually presenting in the hands, and less commonly in the feet. It is frequently misdiagnosed and behaves aggressively with a high metastatic rate (14%)1. There is a high recurrence rate of 50% with no further treatment versus 5% in those who undergo WLE/amputation1. There is no population-based study looking at incidence, management and outcomes in the literature
Methods
The New Zealand Cancer Registry was searched for all instances of DPA from 2003-2023, and patient health records were retrieved, including referral and clinic letters, operation notes, histology reports and imaging reports.
Results
19 cases were identified with an incidence of 0.19 cases per 1,000,000 person years, which increased over the study. The male:female ratio was 2.8:1, with a median age of 65. Lesions had been present for a mean of 22.2 months prior to diagnosis. 10.5% (2/19) lesions were excised with margins >/= 1mm, and further surgery was performed in 94% (16/17) of the remaining cases. Wide local excision with >5mm margins was performed in seven, and amputation in eight. Sentinel lymph node biopsy (SLNB) was performed in four cases. There was one incidence of recurrence (5.1%), and two cases of metastatic disease (10.5%). Mortality rate was 5.1%.
Conclusion
Digital papillary adenocarcinoma is commonly misdiagnosed clinically, with a history of trauma in 42.1%, meaning all finger lesion excisions should be sent for histological examination. All patients should undergo a wide local excision or digital amputation. There is a rate of metastatic disease at presentation, and SLNB can be considered. Given the high rate of metastatic disease, patients should be followed up for a prolonged period, both clinically and with screening chest x-rays.