Apocrine differentiation is usually seen Often with decapitation secretion • Outer layer of cuboidal myoepithelial cells • Variable degree of mitotic index Top Differential Diagnoses • Syringocystadenoma papilliferum (SCP) Similar histologic features, indicating…
Deep subcutaneous/fascial/muscular extension, necrosis, &/or lymphovascular invasion Shows no identifiable line of differentiation (i.e., diagnosis of exclusion) • Synonyms: Superficial malignant fibrous histiocytoma, undifferentiated pleomorphic sarcoma of skin Clinical Issues • Older…
Presence of keratocysts allows for distinction (absent in eccrine carcinoma) • Adenoid cystic carcinoma Cribriform architecture allows distinction (generally absent in eccrine carcinoma) • Infiltrative basal cell carcinoma Lacks true lumen formation…
Only a few cases have metastasized, usually to lymph nodes and lungs Macroscopic • Usually a few centimeters, can be up to 8 cm Microscopic • Composed of infiltrative lobules, islands, and…
No nuclear β-catenin labeling but cytoplasmic labeling common • Inclusions show granular &/or filamentous features by EM • Cytoplasmic filaments extend onto inclusions Infantile Digital Fibromatosis/Inclusion Body FibromatosisClinical examination of infantile digital…
Cutaneous müllerian cyst Eccrine cutaneous ciliated cyst Etiology/Pathogenesis • Müllerian (paramesonephric) heterotopia • Metaplasia of sweat gland epithelium Clinical Issues • Cutaneous müllerian cyst: Typically affects limbs of young female patients • Eccrine cutaneous…
a.k.a. NAME (nevi, atrial myxomas, myxoid neurofibromas, and ephelides) and LAMB (lentigines, atrial myxomas, and blue nevi) syndromes If patient has multiple cutaneous myxomas, should consider Carney complex Clinical Issues…
Less commonly: Lateral, thyroid, or subcutaneous • M:F = 4:1 • Presents with airway compression, dysphagia, or infection, or may be asymptomatic • Complete surgical excision is treatment of choice • Excellent long-term clinical…
May also represent later stage/regressing variant of trichofolliculoma, but is typically dermal-based tumor with prominent sebaceous glands • Dilated pore of Winer Cystically dilated follicle that communicates with overlying epidermis • Trichoepithelioma…
Predominantly composed of atypical squamous cells, with scattered melanocytes – Melanocytes Of low density Single, not nested Dendritic shaped Nuclei not atypical • Pseudoepitheliomatous hyperplasia associated with malignant melanoma Keratinocytes in hyperplastic…
