Olfactory ensheathing cell tumor with neurofibroma-like features: a case report and review of the literature

Abstract

A 32-year-old man had seizure attack since April 2008 and radiographic examination revealed a heterogeneous enhancing mass at the left subfrontal region. He underwent craniotomy for tumor removal on October 1, 2008. The tumor, which was grayish white with glistening appearance and rubbery consistency, was traced to the proximal part of left olfactory tract. Histopathological examination revealed a hypocellular tumor with dense hyalinization in most areas. The tumor cells had ovoid to elongate and often comma-shaped nucleus. Myxoid change of the stroma was apparent in places. Most of the tumor cells were immuno-reactive for S-100 protein. Staining for Leu 7 (CD57 or HNK-1) was negative. Bodian method illustrated many axons within the tumor. Ultrastructural study of the tumor cells showed features compatible with those of olfactory ensheathing cell. The tumor was designated as olfactory ensheathing cell tumor with neurofibroma-like features. There have been 14 nerve sheath tumors arising from the olfactory nerve reported in the literature; all of them had the morphology of schwannoma. Our case, which had the morphology simulating neurofibroma was the first of its kind to be recorded.

Olfactory ensheathing cell tumor: A case report and review of the literature

“…This is younger than that of patients with schwannomas (9). As OECTs are located in the anterior fossa close to the olfactory nerve, olfactory dysfunction is a common clinical manifestation (1,(3)(4)(5)(6)(7)(8). Five of the seven cases reported in the literature presented with anosmia, including two cases with right-sided anosmia, two cases with bilateral anosmia and one case with hyposmia.…”

“…It is also necessary to differentiate these malignancies from common meningiomas in the anterior fossa (2). OECT was first identified as a distinct entity by Yasuda et al in 2006 (1), and only seven cases have been reported to date (1,(3)(4)(5)(6)(7)(8). Therefore, little information is available with regard to the clinical, radiological and immunohistochemical characteristics of OECTs (5).…”

Globose, cystic olfactory ensheathing cell tumor: A case report and literature review

“…OECT may be treated surgically using the endoscopic transnasal approach or craniotomy. OECT has an extremely good prognosis, with a reported 2-year survival rate of 100% (2,(5)(6)(7)(8)(9)(10)(11). The present study reports the ninth case of OECT, which included confusing radiographic features, and presents a review of the literature.…”

“…Thus, OECs may be considered an intermediate glial cell type that originate in the CNS, but function in the PNS. Furthermore, olfactory neuroblastoma has been reported to originate from the sensory neurons of the olfactory mucosa, and to involve the superior nasal cavity or the cribriform plate, while OGM has been reported to originate from arachnoidal cap cells as a truism (7,18).…”

“…Despite its rarity, ~50 cases of subfrontal olfactory groove schwannoma (OGS) and 8 cases of OECT, with clinical and radiological features similar to those of meningiomas and neuroblastomas in the midline of the anterior cranial fossa, have been published worldwide to date (2)(3)(4)(5)(6)(7)(8)(9)(10)(11). The biological behaviour of OECT is currently unknown; The previous cases reported a benign course and a short follow-up time (2,(5)(6)(7)(8)(9)(10)(11). OECs resemble Schwann cells on light and electron microscopy; however, the presence of cluster of differentiation 57, also known as Leu-7, is considered to differentiate OGS from OECT (2).…”