Microcystic/Reticular Schwannoma of the Frontal Lobe: An Unusual Occurrence

Abstract

Schwannoma is a benign peripheral nerve sheath tumor that typically involves cranial nerves of the head and neck region. Intraparenchymal occurrence of this tumor is uncommon. Even rarer in this site is the microcystic/reticular pattern of schwannoma. This histologic variant, first described in 2008, has a predilection for visceral organs. Herein, we report the first case of microcystic/reticular schwannoma of the frontal lobe.

Frontal lobe intracerebral schwannoma mimicking metastatic lesion in a patient with papillary thyroid carcinoma

“…The origin of intracerebral schwannomas is much debated in the literature [ 2 ]. Since Schwann cells are not indigenous to cerebral parenchyma, substantial speculation has been attached to their origin [ 6 ].…”

“…One is that they have a developmental origin related to native CNS cells, such as the mesenchymal pial cells or neural crest cells. Another theory attributes the presence of Schwann cells to the perivascular nerve plexuses of penetrating vessels [ 2 , 4 ].…”

“…Several characteristic findings have been described, although significant variability exists. These lesions are often superficial or periventricular in location and may be enhanced homogenously or heterogeneously [ 2 , 5 ]. The presence of a cyst has been the most consistent finding with these tumors [ 6 ].…”

“…Intracerebral occurrences of schwannomas are uncommon, with the first known report in 1966 by Gibson et al [ 1 ]. Since then, over 65 additional cases of intracerebral schwannomas have been described [ 2 , 8 ]. These lesions are generally solitary.…”

“…An association with neurofibromatosis was described in some reports [ 6 , 9 ]. Prospective imaging diagnosis is challenging due to a lack of pathognomonic features [ 2 ]. Although common neuroradiological characteristics of intracerebral schwannoma are thought to be calcifications, cystic formations and peritumoral edema, these findings are not the rule [ 8 ].…”