Primary intracranial squamous cell carcinoma originating in cerebellar parenchyma: a case report and literature review

Primary intracranial squamous cell carcinoma (SCC) is an exceptionally rare central nervous system malignancy, most often reported in association with malignant transformation of an intracranial epidermoid cyst. A cerebellar parenchyma-centered presentation without a clearly demonstrable extra-axial epidermoid cyst or cerebellopontine-angle origin is particularly unusual and diagnostically challenging. A 53-year-old woman presented with persistent headache. Magnetic resonance imaging demonstrated a 3.5 × 2.8 × 3.9 cm heterogeneously enhancing cerebellar mass with marked perilesional edema and compression of the fourth ventricle, raising suspicion for high-grade glioma or metastatic disease. Gross total resection was achieved through a posterior midline approach. Intraoperative frozen-section examination supported squamous cell carcinoma (SCC), and permanent sections confirmed moderately differentiated SCC. No benign epidermoid cyst lining or adjacent benign squamous epithelial component was identified in the 12 hematoxylin-eosin-stained sections reviewed. Whole-body positron emission tomography/computed tomography performed 1 month after surgery did not identify an extracranial primary tumor. Local recurrence was detected 6 months after surgery, and the patient received intensity-modulated radiotherapy to a total dose of 52.2 Gy in 24 fractions. At the last telephone follow-up, 19 months after the initial surgery, survival was confirmed; however, objective post-radiotherapy imaging and neurological examination were unavailable. This case highlights the diagnostic challenge of primary intracranial SCC and underscores the importance of histopathological confirmation. The epidermoid-related origin remains plausible but unproven, and conclusions are limited by the single-case nature of this report.