Brain Pathology Case of the Month - January 2019

Contributed by Foschi M1, Rizzo G2, Zoli M2,3, Mazzatenta D1,2,3, Marliani F2,4, Foschini MP2,5, Avoni P2, Liguori R1,2
Department of Biomedical and Neuromotor Sciences, University of Bologna1. IRCCS Istituto delle Scienze Neurologiche di Bologna2
    Center of Pituitary and Endoscopic Skull Base Surgery3, Division of Neuroradiology4, Divison of Anatomic Pathology5


CLINICAL HISTORY and IMAGING

A 36-year-old woman was referred to our unit for subacute onset (within 2 months) of right eye ptosis and unreactive mydriasis. The patient complained of photophobia, right ocular dryness and progressive inability in focusing on images. A neurological examination at a local emergency room found incomplete III cranial nerve palsy. A CT scan was normal. The right fundus oculi evaluation with optic coherence tomography (OCT) showed papillary edema. Visual fields examination showed blind spot enlargement in the right eye. An MRI showed slightly T2 hyperintense tissue enlarging Meckel's cave and involving the carotid artery (Figs. 1a, 1b). The mass involved the right temporal dura, the cavernous sinus and extended into the right orbit through the superior orbital fissure (Figs. 1c, 1d). The right superior orbital fissure enlargement was well documented by an orbital CT scan (3D reconstruction, Fig. 1e). After Gd administration, it presented intense and homogenous enhancement (Figs. 1f, 1g) leading to the suspect of a lymphomatous or granulomatous lesion (neurosarcoidosis, Tolosa-Hunt syndrome). During the admission the patient underwent a complete serological investigation for infectious diseases and autoimmune disorders which resulted negative except for a slightly increased ACE level (57, n.v. = 8-52). Blood Calcium and parathormone (PTH) level were normal. The cerebrospinal fluid (CSF) biochemical analysis did not show any significant alteration and atypical lymphocytes were not found. Visual evocated potential showed normal latencies with increased cortical responses amplitudes. A chest CT scan showed only a small ground glass area in the apical segment of the right inferior pulmonary lobe. There were no radiological signs of interstitial abnormalities or mediastinal lymphadenopathy. A high dose corticosteroids (CCS) cycle was tempted without significant clinical improvement. After few days, the right eye ptosis consistently worsened and the patient developed right lateral gaze diplopia and hypoesthesia in the second trigeminal branch (V2) territory. After the CCS cycle a second MRI was repeated showing a diffuse increase of the lesion enhancement after Gd administration. It also involved the right muscle cone and the sheets of the right optic and trigeminal nerve through the oval foramen thus compressing the right carotid syphon. The mass infiltrated the left internal pterygoid muscle and extended in the left part of upper nasopharynx. Therefore, the patient underwent endoscopic endonasal biopsy performed through a bilateral anterior sphenoidectomy and a right transmaxillo-pterygoid approach to the pterygopalatine fossa.

HISTOPATHOLOGY

At surgical exploration the mucosa of the sphenoidal sinus resulted thick and it was removed for histological analysis. In the right pterygopalatine fossa, an invasive whitish tissue hard in consistency infiltrated the vidian nerve and the V3, enlarging the foramen rotundum. Multiple samples of this tissue and from the vidian nerve were collected to assess the perineural extension of the tumor. At histopathological analysis of these samples showed an invasive carcinoma. Specifically, the tumor was composed of nests of neoplastic cells, showing a biphasic pattern. The central part of the nests showed glandular spaces, surrounded by an inner layer of eosinophilic cells and by multiple outer layers of clear cells (Fig. 1h). Numerous atypical mitoses were present. No necrosis was seen in the biopsy. On immunohistochemistry, the biphasic pattern was evidenced, as the eosinophilic cells were immunoreactive with cytokeratin 7 (CK7) (Fig. 1i) and CD117 (c-Kit) (Fig. 1j), while the outer layer was positive with smooth muscle actin (Fig. 1k). CD117. Positivity mainly localized in the inner cell layer. Proliferative activity was evaluated by Ki67 immunostaining that was positive in 20% of the neoplastic cells (Fig. 1l). What is your diagnosis?

FINAL DIAGNOSIS


International Society of Neuropathology