Ch. 26 - Metastatic tumors and simulators Flashcards
What are the most common adenocarcinoma metastases to skin?
How can glandular differentiation be highlighted?
What IHC suggests primary cutaneous adnexal tumors over metastatic adenocarcinoma?
Breast or lung
Mucicarmine staining
CK5/6 and p63 positivity
Breast carcinoma
Poorly differentiated adenocarcinoma with many patterns and occasional epidermotropism. GCDFP15+, ER+, CK7+
Carcinoma en cuirasse
Woody induration of skin with dense dermal collagen and single files of hyperchromatic cells with nuclear molding. Rectangular punch!
Inflammatory carcinoma (carcinoma erysipeloides)
Tumor cells within dilated lymphatic vessels with congested capillaries
Alopecia neoplastica
Sclerotic dermis with infiltrative cords of atypical cells and loss of hair follicles.
Lung carcinoma
Most common skin met in men. Can be adeno/SqCC/SLCL….TTF1+.
Small cell lung carcinoma
Sheets of uniform round blue nuclei with little cytoplasm and nuclear molding. TTF1+ (vs Merkel cell)
Renal carcinoma
Tubules of clear glycogenated cells with prominent vascular (chicken-wire) component. CD10+, PAS+, RCC+
Colon carcinoma
Moderately-differentiatd adenocarcinoma, often mucinous. CK20+, CK7-, CDX2+
Ovarian carcinoma
Well-differentiated adenocarcinoma sometimes with papillary fronding or psammoma bodies. CK7+, CA125+
Signet-ring carcinoma
Usually gastric but sometimes breast or other GI primary. Mucin compresses nucleus to periphery. Loose stroma.
Thyroid carcinoma
Papillary or follicular. “Orphan Annie” nuclei and psammoma bodies. Thyroglobulin/TTF1+
Prostate carcinoma
Poorly differentiated adenocarcinoma infiltrating through collagen. PSA+
Metastatic squamous cell carcinoma
Deeper dermal tumor with squamous pearls and no epidermal connection. EMA/pankeratin+
Meningioma
Spindled to ovoid cells in whorls or groups. Sheet-like syncytia, psammoma bodies. EMA+