Hernando Mena

Malignant transformation of a dysembryoplastic neuroepithelial tumor after radiation and chemotherapy

We describe a case of anaplastic astrocytoma in a 14-year-old boy arising at the site of a dysembryoplastic neuroepithelial tumor (DNT) 3 years after combined radiation and chemotherapy. The subtotally excised superficial right temporoparietal tumor was originally diagnosed as mixed oligoastrocytoma in 1974; the patient was treated with radiation therapy postoperatively. One year later he underwent a craniotomy to remove cyst fluid and no change was reported in the size of the residual tumor. Postoperatively, he received a 6-week course of chemotherapy (lovustine, CCNU). He remained clinically and radiographically stable until 3 years later, when seizure activity returned and imaging studies were consistent with tumor recurrence. He was lost to follow-up until 1986, when records showed that he had died. Review of the initial biopsy showed cortical fragments containing abundant calcifications and multinodular structures typical of the complex form of DNT, in addition to specific glioneuronal elements. The Ki-67 labeling index ranged from 0.1% to 3% focally. The specimen from the third surgery showed an anaplastic astrocytoma (Ki-67 up to 12%) and morphologic features characteristic of radiation effect. This is the first documented case of malignant transformation of DNT following radiation and adjuvant chemotherapy. The implications of malignant transformation in subtotally excised complex DNTs and the intriguing issue of the contribution of radiation/chemotherapy are discussed.

Primary Ear and Temporal Bone Meningiomas: A Clinicopathologic Study of 36 Cases with a Review of the Literature

“Primary” ear and temporal bone meningiomas are tumors that are frequently misdiagnosed and unrecognized, resulting in inappropriate clinical management. To date, a large clinicopathologic study of meningiomas in this anatomic site has not been reported. Thirty-six cases of ear and temporal bone meningiomas diagnosed between 1970 and 1996 were retrieved from our files. Histologic features were reviewed, immunohistochemical analysis was performed (n = 19), and patient follow-up was obtained (n = 35). The patients included 24 females and 12 males, aged 10–80 years (mean, 49.6 years), with female patients presenting at an older age (mean, 52.0 years) than male patients (mean, 44.8 years). Patients presented clinically with hearing changes (n = 20), otitis (n = 7), pain (n = 5), and/or dizziness/vertigo (n = 3). Symptoms were present for an average of 24.6 months. The tumors affected the middle ear (n = 25), external auditory canal (n = 4), or a combination of temporal bone and middle ear (n = 7). The tumors ranged in size from 0.5 to 4.5 cm in greatest dimension (mean, 1.2 cm). Radiographic studies demonstrated a central nervous system connection in 2 patients. Histologically, the tumors demonstrated features similar to those of intracranial meningiomas, including meningothelial (n = 33), psammomatous (n = 2), and atypical (n = 1). An associated cholesteatoma was identified in 9 cases. Immunohistochemical studies confirmed the diagnosis of meningioma with positive reactions for epithelial membrane antigen (79%) and vimentin (100%). The differential diagnosis includes paraganglioma, schwannoma, carcinoma, melanoma, and middle ear adenoma. Surgical excision was used in all patients. Ten patients developed a recurrence from 5 months to 2 years later. Five patients died with recurrent disease (mean, 3.5 years), and the remaining 30 patients were alive (n = 25, mean: 19.0 years) or had died (n = 5, mean: 9.5 years) of unrelated causes without evidence of disease. We conclude that extracranial ear and temporal bone meningiomas are rare tumors histologically similar to their intracranial counterparts. They behave as slow-growing neoplasms with a good overall prognosis (raw 5-y survival, 83%). Extent of surgical excision is probably the most important factor in determining outlook because recurrences develop in 28% of cases.

Mycobacterial spindle cell pseudotumor of the brain: A case report and review of the literature

Spindle cell pseudotumors found in the skin, lymph nodes, bone marrow, spleen, lungs, and retroperitoneum have been reported recently in immunosuppressed patients, including those with acquired immunodeficiency syndrome. The authors report a similar lesion limited to the brain in a 38-year-old human immunodeficiency virus-negative man receiving steroid therapy for treatment of sarcoidosis. Histopathologically the lesions were composed of spindle and epithelioid histiocytes, small foci of necrosis, and numerous acid-fast bacilli. The acid-fast bacilli were determined by culture and polymerase chain reaction to be Mycobacterium avium intracellulare. Because of the uncommon histologic appearance of this lesion and the potential for treatment if recognized, mycobacterial spindle cell pseudotumors should be included in the differential diagnosis of spindle cell lesions in the brain in immunosuppressed patients.

Immunohistochemical characterization of pineal parenchymal tumors using novel monoclonal antibodies to the pineal body.

To characterize the immunohistochemical nature of pineal parenchymal tumors (PPT), we examined nine cases of normal pineal bodies and 23 cases of PPT using several neuronal and glial antibodies and 10 novel monoclonal antibodies raised against human pineal tissue. The PPT were classified into four pineocytoma, five pineal parenchymal tumor of intermediate differentiation (Int‐PPT), and 14 pineoblastoma. The pinealocytes, parenchymal cells of the pineal body, were labeled with five neuronal and seven pineal monoclonal (from PP1 to PP7) antibodies in the normal pineal bodies. The subjects ranged from 3 to 85 years old, 12 female and eight male subjects were studied. Antibodies to glial cells PI1, PI2 and PX1, stained interstitial cells of the pineal body. Many of the PPT showed positive immunostaining for pinealocyte‐associated antigens and neuronal markers. The intensity of immunostaining showed some association with the degree of differentiation of the tumor, but there was a considerable variety of staining from case to case. The pineocytomas are more immunopositive than are the Int‐PPT or pineoblastoma for neuronal and pinealocyte‐associated antibodies. In particular the neurofilament protein (NFP)68 kDa, PP1 and PP6 showed significant differences of reactivity between pineocytoma, Int‐PPT and pineoblastoma, when compared in groups showing extensive positive staining (positive staining in almost all areas of the tumor). By using three representative antibodies, anti‐NFP68kDa, PP1 and PP6, we were able to make a clear distinction between pineoblastoma, Int‐PPT and pineocytoma. Glial fibrillary acidic protein (GFAP), PI1 and PI2 antibodies only occasionally showed a small number of positive cells in the tumor, and thus we considered these cells to be non‐neoplastic interstitial cells or reactive astrocytes entrapped in the tumor. Our data suggest that the glial differentiation of PPT may occur, but that it seems to be a very rare event.

Mesencephalic cryptococcal abscesses presenting with parkinsonism as an initial manifestation of AIDS.

Parkinsonism has been associated with HIV/AIDS and cerebral cryptococcal disease, but to date there has been no report of histological cryptococcal lesions in the substantia nigra (SN) in a patient with parkinsonism. We report on a case of a 63‐year‐old man who presented with tremor, gait disturbance, and mask‐like facies, and showed cryptococcal meningoencephalitis with cryptococcal abscesses in the SN at autopsy, without Lewy bodies or significant degeneration of the SN neurons. Parkinsonism also represented the first manifestation of AIDS in this previously undiagnosed patient. This case highlights the importance of considering infectious etiologies in patients presenting with parkinsonism, and underscores the need for autopsy in evaluation of patients with new or unexplained movement disorders. Movement disorders in association with AIDS and mesencephalic mass lesions are discussed.