Intracranial angioleiomyoma mimicking meningioma: an uncommon tumor with favorable outcome and frequent GJA4 mutation.

Intracranial angioleiomyoma (IALM) is a rare neoplasm mimicking meningioma. We aimed to explore the clinical and molecular characteristics of IALMs. We included 40 patients with IALMs who had tumor resection at our center from 2009 to 2022. Clinicopathological and radiological characteristics were extracted and analyzed thoroughly. GJA4 mutation status was detected and correlated with clinical characteristics. IALMs accounted for about 10% of all angioleiomyoma and had a significant male predominance compared to extracranial angioleiomyoma (p=0.04). However, there was no age difference between extracranial angioleiomyomas and IALMs. In our IALM cohort, orbital (35%) were the most common tumor location, followed by tentorium (25.0%), cavernous sinuous (17.5%). Vision decrease, diplopia and exophthalmos (40%) were the most common symptom. The radiological characteristics of ILAMs were similar to meningiomas; 20 patients (57.1%) in our cohort were misdiagnosed as meningioma preoperatively. Gross total resection was achieved in all patients. The postoperative pathology showed median Ki-67 index was 1% (range: 0-10%). Vision improvement or exophthalmos relief was achieved in 12 of 16 patients (75.0%). During the long-term follow-up (mean 70.3 months, range 30 - 128 months), no patient experienced tumor recurrence or died of tumor progression, indicating that IALM was clinically benign. GJA4 mutation (p. Gly41Cys) was detected in 17 (42.5%) patients. Of note, the correlations analysis revealed that orbital and cavernous sinus areas (64.7%) were the leading location that harbor GJA4 mutations. Tumors with mutant GJA4 were associated with positive progesterone receptor (PR) expression (p=0.02). This first large case series demonstrated that IALM predominantly affected males, was located in the cavernous sinus and orbital areas, and often manifested visual impairment and diplopia. IALM had favorable outcome. Notably, IALMs frequently exhibited a GJA4 mutation, which was linked to the cavernous sinus and orbital locations, as well as PR expression.