A man in his 90 s presented with a 1-month history of more than ten 1–2-cm, elastic-hard, mildly bluish subcutaneous nodules distributed across the chest, abdomen, and thighs, without associated pain or systemic symptoms (Fig. 1a-c). The clinical differential diagnosis included cutaneous metastases from solid tumors, subcutaneous melanoma metastases, subcutaneous lymphoma, and subcutaneous sarcoidosis. Skin biopsy demonstrated a diffuse, cord-like infiltration of atypical cells with irregular round nuclei within the subcutis (Fig.
