Primary intracranial pleomorphic angioleiomyoma—A New Morphologic Variant. An immunohistochemical and electron microscopic study

Abstract

Background. Angioleiomyomas usually are benign subcutaneous neoplasms that occur most often in extremities of middle‐aged individuals. Very few cases have been described in other locations; none along the neuroaxis. An intracranial example of angioleiomyoma displaying unusual morphologic features not seen in the typical peripheral variants of this tumor is described. Methods. The tumor was studied with conventional histology, immunohistochemistry with morphometric calculation of proliferation index, immunoelectron microscopy, and DNA flow cytometry. Results. The tumor was composed of large epithelioid and pleomorphic cells filled with intermediate filaments positive for desmin and vimentin. Scattered cells also expressed myosin and muscle‐specific actin. Smooth muscle cell differentiation was confirmed by ultrastructural demonstration of subplasmalemmal dense bodies, attachment plaques, and discontinuous basal lamina. The proliferation index with proliferating cell nuclear antigen (PCNA) monoclonal antibody was 75.78%, whereas it was only 4.22% with Ki67 monoclonal antibodies adopted to paraffin material (MIB‐1). Conclusion. The tumor represents a unique morphologic variant of a pleomorphic angioleiomyoma. Cellular pleomorphism and a strong reaction for PCNA in numerous cells suggested that the lesion was malignant. However, the absence of mitotic figures, a small number of Ki67‐positive cells, a diploic DNA pattern, and a low proliferation index in flow cytometry all supported the concept that this neoplasm represented an unusual histologic variant of benign angiogenic leiomyoma. Encapsulation and demarcation of the surgical specimen and the survival of the patient for more than 4 years without recurrence after resection support this interpretation.

Angioleiomyoma of the Cavernous Sinus: Case Report

“…No cases in the cranial cavity or brain were reported. To date, only two cases of intracranial ALM have been reported: one in the leptomeninges of the parietal lobe (8) and the other in the head of the caudate nucleus (13). No occurrence within the cavernous sinus has been described previously.…”

“…However, a malignant potential for this lesion is doubtful. The prognosis of intracranial ALM is likely good, as suggested by this case and the other two cases previously reported (8,13).…”

“…Intracranial ALMs are extremely rare. To date, only two cases of intracranial ALMs have been described (8,13). Neither of these reported cases of ALM involved the cavernous sinus.…”

Primary Composite Angiogenic Leiomyosarcoma?Epithelioid Angiosarcoma of the Brain

“…The patient underwent another negative Primary smooth muscle cell tumors of the central nervous system ( CNS) are very rare [ 1± 12] . Among the reported cases, three were benign angiogenic leiomyomas [ 5,6,11] and nine were primary intracranial leiomyosarcomas. The latter have been located in the meninges of the brain [ 2] and spinal cord [ 4,12] , sella turcica [ 1] , posterior cranial fossa [ 3] , and in the lateral ventricle [ 7] .…”

Cavernous Angiomyoma of the Internal Auditory Canal

“…In total, 17 patients of intracranial angiomyomas have been reported to date (2,3). The three patients involving the IAC presented with sensorineural hearing loss (2).…”