Aggressive Digital Papillary Adenocarcinoma at Atypical Site

Abstract

Aggressive digital papillary adenocarcinoma (ADPA) is a rare tumour of eccrine origin. They present as asymptomatic nodules with flattened and thickened surface skin, most commonly on fingers and toes. It mimics many benign entities and tumours, hence leading to a delay in diagnosis. It has a high metastasizing potential, but is slowly progressive. Histopathologically, it has both a nodular and a cystic component with papillary projections into cystic spaces. We present a 54-year man with a tumorous mass on right heel, which was diagnosed by histopathology and immunohistochemistry as ADPA. Our case had ADPA lesion, a rarely reported malignancy on an uncommon site with distant metastasis.

Digital Papillary Adenocarcinoma, a Rare Malignant Tumor

“…The age at onset is usually between the fifth and seventh decades (the average is 52 years old) [2], affecting males more often than females (7–9:1) [1, 8]. The tumor commonly presents as a solitary mass, may be located between the nail bed and distal interphalangeal joint [8], but it has also been reported on the palmar surface of the hand, plantar surface of the foot, lower leg, and on the web spaces of hands and feet, with rare cases reported on the lips and ears [9]. Often located on the dermis, DPA can invade deeper structures such as muscles, tendons or bones.…”

“…Local recurrence can occur in 30–50% of the cases after surgical excision, which can be reduced to 5% after excision with a clear resection of the margins [2]. The overall rate of reported metastatic disease is between 14 and 26% [2, 5, 8], being more prevalent in the lungs, but other areas have been observed, such as lymph nodes, brain, skin, bones, and kidneys [8, 9].…”

Current Diagnosis and Treatment Options for Cutaneous Adnexal Neoplasms with Apocrine and Eccrine Differentiation

“…Neoplasm is most frequent in Caucasian men. Patients are usually in the sixth and seventh decades of life, although a few cases of tumors occurring in patients below the age of 20 years have been reported [ 113 ]. The overall incidence is estimated to be 0.08 per 1,000,000 person-years.…”

“…Other skin lesions such as a ganglion cyst, foreign body or pyogenic granuloma, paronychia, glomus tumor, squamous cell carcinoma, hemangioma, giant cell tumor, osteomyelitis, and soft tissue infections should be taken into account in the differential diagnosis. Metastases are usually found in the lungs, followed by lymph nodes, brain, skin, bones, and kidneys, which can develop even after 20 years following initial treatment [ 113 , 116 ]. Histopathologically, it shows solid, cystic, and papillary structures consisting of basaloid tumor cells.…”

“…Necrosis with inflammatory cells may be observed. Focal keratinization, vascular dilatation, and clear cell change have been reported [ 113 ]. The immunohistochemical feature is that all tubular structures stain with CK7 ( Figure 6 B2).…”