Ali G. Saad

Normal Quantity and Distribution of Mast Cells and Eosinophils in the Pediatric Colon

The normal number and distribution of mast cells (MCs) and eosinophils in colonic mucosa are largely unknown. Accordingly, we examined colonic biopsies obtained during endoscopic examinations of pediatric patients. The study included 41 patients (21 males and 20 females). The mean age was 11.72 years (range 3.3–19.7 years). Patients were followed for a mean time of 23.4 months (range 1250 months). Our results showed a gradual decrease in the number of eosinophils in the lamina propria from the cecum to the descending colon (14.2 ± 6.1 and 10.7 ± 5.6 eosinophils//high-power field [hpf], respectively), with another peak in the rectosigmoid (12.4 ± 6.1 eosinophils/hpf). Eosinophils within the surface and crypt epithelium were more commonly encountered in the cecum and the rectosigmoid. Eosinophils clusters were rare but were more frequently found in the cecum and rectosigmoid. The largest number of MCs was observed in the descending colon and the lowest in the rectosigmoid (17.56 ± 7.28 and 14.5 ± 6.35 MCs/hpf, respectively). No MCs were identified within the surface epithelium. Very rare MCs were observed within the crypt epithelium, with the highest number observed in the cecum (0.34 ± 0.53 MCs/hpf) and the lowest number observed in the descending colon (0.02 ± 0.16 MCs/hpf). More MCs were present in the cecum and descending colon of females vs males (P = 0.02 and 0.04, respectively). Our results establish baseline gastrointestinal eosinophils and MC counts in various parts of the pediatric colon.

Radiation-associated meningiomas in children: clinical, pathological, and cytogenetic characteristics with a critical review of the literature

OBJECT Radiation-associated meningiomas (RAMs) arise after treatment with radiation to the cranium and are recognized as clinically separate from sporadic meningiomas. Compared with their sporadic counterparts, RAMs are often aggressive or malignant, likely to be multiple, and have a high recurrence rate. However, limited information exists about the clinical, pathological, and cytogenetic features of RAMs in pediatric patients. The authors report the findings in 9 children with meningiomas following therapeutic radiation to the cranium. In addition, they performed a critical review of the English language literature on pediatric RAMs. METHODS Medical files were searched for patients who demonstrated meningiomas after a history of radiation to the brain. Only those patients in whom a meningioma occurred before the age of 18 years were included in this study. Clinical and demographic data along with the MIB-1 labeling index and cytogenetic studies were evaluated. RESULTS The patients consisted of 5 males and 4 females with a median age of 5 years (range 2-10 years) at radiation therapy. The latency period was a median of 10 years after radiation therapy (range 6-13 years). The MIB-1 labeling index was a median of 6.6% (range 4%-10%). Five patients (55.6%) displayed multiple meningiomas at the first presentation. Histological types included clear cell meningioma in 1 patient, fibroblastic meningioma in 2, chordoid meningioma in 2, meningothelial meningioma in 7 (atypical in 2 cases), xanthomatous meningioma in 1, and chordoid meningioma in 1. Cytogenetic studies showed that the loss of 22q12.2 was the most common abnormality (3 patients), followed by complex cytogenetic abnormalities (2 patients) and rearrangements between chromosomes 1 and 12 (1 patient) and a 1p deletion (1 patient). CONCLUSIONS In contrast to RAMs occurring in adults, those in pediatric patients show an increased incidence of multiplicity on first presentation and unusual histological variants, some of which are described here for the first time. There was no difference in the MIB-1 labeling index in children with RAMs as compared with that in children with non-RAMs.

Ganglioglioma associated with cerebral cortical dysplasia: an unusual case with extensive leptomeningeal involvement.

Ganglioglioma is a tumor occurring in children and young adults and characterized by a superficial cortical location and biphasic histologic differentiation encompassing neuronal and glial elements. Ganglioglioma may arise anywhere throughout the neuraxis, including the optic nerve, brain stem, pineal gland, cerebellum, cerebrum, and spinal cord; however, the majority of glioneuronal neoplasms involve the temporal lobe. Gangliogliomas may show focal leptomeningeal involvement, but predominant leptomeningeal involvement by gangliogliomas is extremely rare; only 2 cases of ganglioglioma extensively involving the leptomeninges have been reported. In this report, we present an unusual case of a ganglioglioma predominantly present within the leptomeninges of a 15-year-old boy with a history of seizures. Furthermore, the cerebral cortex beneath the tumor showed dysplastic changes. We report a very unusual case of ganglioglioma involving predominantly the cerebral leptomeninges and associated with adjacent cerebral cortical dysplasia. Histologic characteristics and diagnostic pitfalls are discussed.

Pilocytic astrocytoma of the spinal cord in an adult

Case presentationA 42-year-old man presented with a 9-month history ofprogressive numbness and paresthesias involving theupper limbs. His symptoms started at the fourth and fifthdigits of both arms, and ascended to involve the elbows.Within several weeks, the lower limbs became involvedwith the numbness and pain starting at the toes andprogressing up to mid thorax. He had no bowel or bladderinvolvement. His examination showed no stigmata ofsystemic disease. He had minimal weakness at hip flex-ion, upper motor neuron signs in all limbs, decreasedsensation in C8 distribution bilaterally, and a sensorylevel at T4 sparing proprioception. Magnetic resonanceimaging (MRI) of the spinal cord 6 and 9 months(September 2006, December 2006) after symptom onsetrevealed T2 prolongation and cord edema (Fig. 1a, c)with an 8 mm enhancing intramedullary lesion at the C5-6 (Fig. 1b, d). The possibility of demyelinating diseasewas considered. Thoracic and brain MRI where unre-markable. Further workup included cerebrospinal fluid(CSF) which revealed leukocytosis of 13 with 88% lym-phocytic predominance, protein of 310 mg/dl, normalglucose and two oligoclonal bands not present in a cor-responding serum sample. The patient continued todevelop progressive neurological deficits that did notrespond to treatment with 5 days of 1 g intravenousMethylprednisolone. Repeated CSF exam showed persis-tence of protein elevation (289 mg/dl), normalization ofleukocytosis and absence of oligoclonal bands. Bothexaminations showed normal cytology. Anti nuclearantibodies (ANA), Lyme serology, angiotensin convertingenzyme (ACE), HTLV-1 serology, B12 level, anti-neutr-ophilic cytoplasmic antibodies (ANCA) were all normal.CT scans of the chest, abdomen and pelvis excludedoccult malignancy and lymphadenopathy. Magnetic reso-nance angiography (MRA) and spinal angiogram showednormal cerebral and spinal vasculature. Repeated spineMRI (February 2007, July 2007) showed mildly increas-ing edema at the site of cervical spinal cord lesion, butstable lesion size and unchanged enhancement pattern.Differential diagnosis included a neoplastic process due tothe persistent duration of enhancement, the elevated pro-tein in the CSF, and absence of clinical or radiographicimprovement after treatment with intravenous steroids.As the etiology of the lesion was not clear preopera-tively, i.e. intramedullary neoplasm or ischemia fromstenosis, the patient underwent C4-T1 decompression,posterior spinal fusion, posterior laminectomy, and intra-dural subtotal mass resection. Intraoperatively the surfaceof the cord and the vasculature looked normal. The cord

Multifocal Supra and Infratentorial Medulloblastoma in an Adult: Histologic, Immunohistochemical, and Molecular Evaluation of a Rare Case and Review of the Literature

Multifocal medulloblastomas (MMBs) in adults are exceedingly rare with only 5 reported cases to date. Medulloblastoma in adult differ from its childhood counterpart by being more often lateral in location, desmoplastic in morphology, and better in clinical prognosis. Little is known, however, about the characteristic features of MMB. This is particularly true for their molecular profiles. To date, molecular characteristics of multifocal medulloblastoma have been reported only once. Here, we present the second case of multifocal medulloblastoma along with its detailed morphology, imaging features, and molecular profiles with a critical review of the literature. We believe that MMB should be reported in detail to better understand their behavior, characterize their molecular profiles, and establish therapeutic protocols.

Giant Frontal Colliding Meningiomas in a Child: Histopathologic, Cytogenetic, and Ultrastructural Descriptions of a Unique Case

Meningiomas in the pediatric population are uncommon primary brain tumors, and rhabdoid meningiomas are exceedingly rare. We describe herein a 16-year-old female who presented with a giant frontal mass with intracranial and extracranial components. Histologic, immunohistochemical, and ultrastructural examinations showed the intracranial tumor to be rhabdoid meningioma, and the extracranial tumor was meningothelial meningioma. Cytogenetic study of the intracranial tumor showed monosomy 22, and the extracranial tumor showed allelic losses at 18p11.32. Because of the different cytogenetic findings and the absence of communication between these two tumors, we concluded that these tumors were separate and represent colliding meningiomas. Furthermore, the rhabdoid meningioma lacked obvious histologic evidence of malignancy. The presence of colliding meningiomas with different cytogenetic abnormalities as well as a rhabdoid meningioma showing no conspicuous evidence of malignancy have not been reported in children before.