Diagnosis: Pilomatricoma (Pilomatrixoma)
An 8-year-old male presenting with a firm, non-tender subcutaneous nodule on the right cheek, gradually enlarging over 6 months.
Solitary, firm to rock-hard, 12mm subcutaneous nodule on the right preauricular cheek. Overlying skin is normal to slightly bluish. Tent sign positive: stretching the overlying skin reveals multifaceted, angular contours of the underlying calcified mass. Non-tender, well-circumscribed.
Mother first noticed the lump 6 months ago; it has slowly grown and become harder. No preceding trauma. No other skin lesions. The child is otherwise healthy with no family history of Gardner syndrome or myotonic dystrophy.
Excisional biopsy performed under local anesthesia. Histopathology showed characteristic basophilic cells and eosinophilic shadow (ghost) cells with areas of calcification and ossification, confirming pilomatricoma. Margins clear. No recurrence expected.
• Epidermal inclusion cyst • Dermoid cyst • Pilomatrical carcinoma • Calcified lymph node • Foreign body granuloma • Basal cell carcinoma
• Also known as calcifying epithelioma of Malherbe • Most common in children and young adults — solitary, firm, deep-seated nodule • "Tent sign": stretching overlying skin reveals multifaceted surface • Histology: basophilic cells (viable) transitioning to shadow/ghost cells (anucleate) — pathognomonic • Calcification and ossification common • Beta-catenin (CTNNB1) mutation — same pathway as Gardner syndrome • Multiple pilomatricomas: consider Gardner syndrome (APC mutation) or myotonic dystrophy • Pilomatrical carcinoma is the rare malignant counterpart
Tags: benign tumor, pediatric, calcification, surgical excision, histopathology