Red Bumps, Red Flags: A Case Series of Four Neoplasms Masquerading as Inflamed Cutaneous Cysts

Red, inflamed cutaneous nodules are frequently diagnosed as epidermal inclusion cysts in both primary care and dermatology settings. However, several benign and malignant entities can closely mimic an inflamed cyst, leading to delayed diagnosis and suboptimal management. We present four patients who initially presented with erythematous nodules clinically suspected to be cysts; final histopathologic diagnoses included dermatofibroma, amelanotic melanoma, dermatofibrosarcoma protuberans, and undifferentiated pleomorphic sarcoma. For each case, we describe the clinical presentation, histopathology, and management. The presence of a central punctum and superficial mobility strongly favors an epidermal inclusion cyst. In contrast, the absence of a punctum, rapid growth, deep fixation, a positive dimple sign, or atypical dermoscopic vascular patterns should raise suspicion for a neoplasm. Final diagnosis is based on histopathologic examination, which guides subsequent treatment in accordance with current guidelines. This series underscores the importance of maintaining a broad differential diagnosis for erythematous nodules and obtaining histopathologic confirmation when clinical features are atypical. Early recognition and appropriate biopsy technique may improve patient outcomes.