Rare case of intracranial histiocytic sarcoma: A case report and literature review

Histiocytic sarcoma (HS) is a rare malignant neoplasm derived from mature histiocytes, typically affecting lymph nodes, the gastrointestinal tract, spleen, soft tissues, and skin. Intracranial occurrence is extremely rare and poses significant diagnostic challenges due to its histopathological resemblance to other aggressive tumors such as anaplastic meningioma.

A 70-year-old man presented with acute right hemiplegia and was found to have two extra-axial lesions with intracerebral hemorrhage in the left frontotemporal region. Initial imaging and immunohistochemistry suggested anaplastic meningioma, and total resection was performed. Six months later, the tumor recurred with brain infiltration and scalp metastasis. However, persistent fever and new neoplastic lesions on whole-body computed tomography (CT), despite negative blood cultures, prompted positron emission tomography-CT, which revealed systemic metastases. This aggressive clinical course led to further immunohistochemical analysis, revealing positivity for cluster of differentiation (CD)68 and CD163, confirming the diagnosis of HS. Due to widespread disease progression, best supportive care was initiated.

This case highlights that HS can radiologically mimic meningioma, even presenting with a classic dural tail sign. Clinicians should remain vigilant for "imaging paradoxes" - where an unusually aggressive clinical course contradicts typical radiological features. In such atypical cases, an expanded immunohistochemical panel including CD68 and CD163 is essential to avoid diagnostic delays and ensure accurate identification.