digital papillary adenocarcinoma

Definition : Aggressive digital papillary adenocarcinomas are rare malignant tumors often located on the digits of the hand. Due to lack of pain, slow growth, and an inconspicuous appearance, diagnosis is often missed or delayed.

Digital papillary carcinoma (DPC) is a rare, slow growing, malignant tumor with eccrine differentiation that occurs predominantly in digits. This tumor was originally classified as a benign neoplasm; aggressive digital papillary adenoma (ADPA) was first described by Helwig in 1979. In 1987, Kao et al. classified ADPA and aggressive digital papillary adenocarcinoma (ADPAca) based on differences in histologic findings.

Images

 https://twitter.com/TheCats33851341/status/1235706775711539200

Microscopy

 multinodular tumor
 well circumscribed nodules in dermis and superficial subcutis
 compact architecture and cystic architecture
 papillary structures, tubular structures or ductal structures
 two cell layer (myoepithelial cells )
 fused glands / lined by cuboidal cells with myoepithelial cells at the periphery
 solid area
 focal necrosis
 increased mitoses
 sheet-like growth pattern
 focal squamous differentiation
 small nest
 lymphatic invasion

 +/-

• infiltrative margin
• epidermal hyperplasia
• epidermal ulceration
• focal epidermal connection

 tumor cells

• basaloid tumor cells
• cuboidal tumor cells
• low columnar tumor cells
• myoepithelial tumor cells
• mild nuclear atypia to moderate nuclear atypia
• +/- severe nuclear atypia
• +/- tumor necrosis
• mitoses may be inconspicuous or frequent
• +/- spindle cell
• +/- squamoid differentiation
• +/- clear cell changes

Etiopathogeny

 HPV42

Differential diagnosis

 hidradenoma
 papillary eccrine adenoma
 apocrine hidrocystoma / apocrine cystadenoma
 microcystic adnexal carcinoma
 hidradenocarcinoma
 epithelial myoepithelial carcinoma / adenomyoepithelial carcinoma

 glandular architecture

• metastatic adenocarcinoma

Open references

 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4386778/
 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4284491/