Tentorial Angioleiomyoma: A Rare Neurosurgical Entity. Case Report and Review of the Literature.

BACKGROUND: Angioleiomyoma (ALM) is a soft tissue neoplasm rarely described in the intracranial site. Because of their uncommon presentation, atypical neuroradiologic and pathologic features, ALMs are often misdiagnosed. CASE DESCRIPTION: We describe the neuroradiologic, clinical, and pathologic data of a 37-year-old male patient suffering from a tentorial ALM. He was admitted at our hospital because of a posterior cranial fossa mass. Magnetic resonance imaging (MRI) showed a left tentorial tumor, hypointense on T1-weighted sequences, with heterogeneous contrast enhancement after gadolinium injection ("salt-and-pepper" fashion) and slightly hyperintense signal on T2-weighted sequence. After surgery, pathological examination showed a tumor composed of several thick-walled blood vessels mixed with a population of deeply eosinophilic spindle-shaped smooth muscle cells arranged in bundles. Necrosis was absent. Neither cellular pleomorphism nor mitoses were detected. Immuno-histochemical analysis confirmed the smooth muscle phenotype of the spindle cell component: diffuse and strong positivity for alpha-smooth muscle actin, desmin, and h-caldesmon. Based on both morphologic and immunohistochemical findings, a diagnosis of primary intracranial ALM was rendered. CONCLUSIONS: We add to the literature the tenth case of this exceedingly rare tumor and submit that ALM should be suspected when a tentorial mass with a "flame-like" time-dependent pattern of contrast enhancement on MRI, a "salt-and-pepper" post-contrast appearance on MRI T1-weighted sequences, and a relation with large intracranial feeding vessels are present.