An Unusual Bump on the Head: Intracranial and Extracranial Cytokeratin-Positive Interstitial Reticular Cell Tumor.

Abstract

We describe a cytokeratin positive interstitial reticulum cell tumor (CPIRCT) as the cause of a large and defacing scalp tumor. Clinically these tumors manifest as progressive, painless swelling. Treatment usually consists of surgery with or without irradiation; chemotherapy is applied in metastatic disease. A patient was referred after attempted removal of a large bump on the head. The tumor was initially noted about 12 months earlier. Assuming a benign lipoma, resection without prior imaging was attempted. During surgery, the underlying bone was found to be profoundly destroyed. Cranial magnetic resonance imaging revealed a large mass with an extracranial and intracranial component. Subsequent extensive resection finally led to the diagnosis of CPIRCT. Most CPIRCTs manifest as progressive palpable or visible masses. Radical excision is usually the mainstay of treatment, although there is no generally accepted treatment strategy. A needle biopsy might not be diagnostic and can complicate future curative surgery. Especially in fast-growing lesions, imaging studies should be considered before surgery. Their potential recurrence and metastatic spread render CPIRCTs an interdisciplinary challenge and highlight the need for long-term follow-up.