Brain Pathology Case of the Month - June 2010

Contributed by by Julio César Gutiérrez Morales, MD, PhD1, Sandra Eugenia Gutiérrez Morales1,2 and Aurora Astudillo González, MD, PhD3
    1. Department of Neurosurgery, Hospital Universitario Central de Asturias, Oviedo, Spain
    2. Faculty of Biological Sciences, University of Oviedo,Spain
    3. Department of Clinical Neuropathology, Hospital Universitario Central de Asturias, Oviedo, Spain


CLINICAL HISTORY

In October 2008, a 72-year-old man was referred to us with a three week history of dizziness and unsteady gait.

In 1963, at the age of 27 years, he suffered an ocular impact by coal stones at work. After the event, a residual dark spot (probably a "coal tattoo" by inclusion) persisted in the conjunctiva. In 2004, he began to feel discomfort in the "tattooed eye". Owing to progressive growth of the old lesion close to limbus-sclera border his ophthalmologist decided to resect it. Malignant melanoma compounded by epithelioid and spindle cell was confirmed histopathologically. The laminar specimen measured 0.7 x 0.5-cm and the initial intraoperative impression about the tumor extended to the peripheral and deep margins was not confirmed after the histopathological exam. Further conservative management with local chemotherapy (mitomycin in drops) was indicated. The patient has undergone periodic ophthalmic and systemic evaluation. Systemic evaluation included palpation of lymphatic chains, routine hematological and biochemical examinations, chest x-ray and abdominal ultrasound study. He did not show local relapse but an impairment of visual function secondary to chemotherapy was observed. The patient did not give any history of systemic complaints until October 2008 when he developed unsteady gait and dizziness.

At the admission in October 2008, neurological examination revealed mild dysmetria and hypotonia in left limbs. Cranial MRI detected a 3 x 2.5 x 2.5-cm-sized intraaxial lesion, hyperintense on T1 and T2-weighted images, with heterogenous enhancing. It was located on the tentorial surface of the left cerebellar hemisphere (left paraculminal area) showing mild perilesional edema (Figures 1 and 2). The preoperative evaluation was completed with a whole body-CT, which did not reveal any evidence of metastasis. In view of those findings, the patient was consented for surgery. He underwent total microsurgical resection via paramedian supracerebellar approach in sitting position. During the operation, the tumor was found to be a blackish soft, suckable mass with poorly defined boundaries. The surgical appearance was typical for a pigmented metastasis. A small piece of tumor was submitted to perform histopathological examination. He had an uneventful post-operative period and the postoperative CT did not show residual tumour. He underwent whole brain radiotherapy and adjuvant chemotherapy. The patient was neurologically symptom-free on follow-up after 3 months.

PATHOLOGICAL EXAMINATION

Conjunctival specimen: A review of the primary conjunctival lesion, obtained from other hospital, showed a slide section, with a transversal representation of 1,3 x 0,8 cm. The microscopic examination showed conjunctiva with an intraepithelial pigmented lesion, formed by invasive epithelioid cells invading 2 mm in depth of the stroma (Figures 3, 4 and 5). The lateral and deeper borders were seemingly free of tumor, with partial squamous metaplasia (Figure 6). There was no evidence of a benign Ota´s nevus.

Brain specimen: Brain lesion on macroscopic examination was a grayish soft mass, measuring 1,5 x 0,9 x 0,7 cm. The microscopy showed a compact tumor, formed by epithelioid anaplastic cells, organized in perivascular aggregates. There was a high mitotic index and some cytoplasmic melanin (Figures 7, 8 and 9).

FINAL DIAGNOSIS


International Society of Neuropathology