Pathology of Digital Papillary Adenocarcinoma

Dr Sampurna Roy MD 2022

Answer - Digital Papillary Adenocarcinoma

Digital Papillary Adenocarcinoma is a rare variant of sweat gland carcinoma of the digits and volar surfaces which has the potential for highly aggressive biological behaviour.

Papillary lesions of the digits were first described in 1987.

Based mostly on histologic criteria these lesions were subtyped as:

(i) Aggressive digital papillary adenoma.

(ii) Aggressive digital papillary adenocarcinoma.

Subsequent follow-up has shown that it was not possible to distinguish reliably these two entities.

Neither clinical nor histologic features were indicative of biologic behavior of these tumours.

Metastatic disease occurred equally with either Aggressive digital papillary adenoma or Aggressive digital papillary adenocarcinoma.

The term 'adenoma' was abandoned as all papillary digital neoplasms seemed to have an aggressive behaviour despite benign histologic appearance.

Site: Occurs exclusively on fingers, toes and adjacent skin of palms and soles.

Clinical presentation: Presents as a solitary, painless, cystic nodule, usually less than 2cm in diameter.

Gross features: Tumour has been described as being tan-gray to white-pink and rubbery.

[Pathology Infographic]- A Slow growing malignant tumour- Digital Papillary Adenocarcinoma

Microscopic features:

- A poorly circumscribed lesion which involves dermis and subcutis ;

- Consists of both solid and cystic components ;

- Tubulo-alveolar and ductal structures with areas of papillary projections protruding into cystic lumina ;

- Cribriform pattern may be present ;

- Glandular structures contain eosinophilic material ;

- Solid area is characterized by back-to-back glands lined by cuboidal or low columnar epithelium ;

- Backround stroma displays thin fibrous septa to areas of dense hyalinized collagen ;

- Mitotic figures are noted ;

- Cytologic atypia is usually not striking.

- Some cases show poor glandular differentiation, poorly defined borders, clear cut infiltrative properties, focal necrosis and cytological evidence of malignancy.

- There may be invasion of soft tissues, blood vessels and underlying bones.

Immunohistochemistry: Immunopositive for S100 protein, CEA and cytokeratin.

Recognition of these tumors is important because of a potential risk of local recurrence ( 40 - 50% of patients) and distant metastases (14% of patients), usually involving lymph nodes and/or lungs.

Aggressive surgical treatment consisting of wide local excision with clear margins and close surveillance for signs of recurrence or metastasis are indicated for this rare sweat gland neoplasm.

Differential diagnosis:

May be misdiagnosed particularly for a metastasis of papillary adenocarcinoma originating in the colon, thyroid, or breast. Clinicopathological correlation is essential to rule out a possible risk of metastatic carcinoma of the skin.

Papillary Eccrine Adenoma: The ductal structures are larger and more dilated than those in the papillary eccrine adenoma.