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Biomedical subjects

Michael B McDermott

Publications and source records attributed to Michael B McDermott.

5 recordsLinked to original sources

Primary desmoplastic small round cell tumor of bone: report of a case with cytogenetic confirmation.

We report a case of desmoplastic small round cell tumor occurring in the right ilium of a 13-year-old boy. Morphologically, the neoplasm consisted of small round cells of primitive appearance with a diffuse growth pattern replacing marrow space and eroding bone. Immunohistochemical staining was positive for vimentin, synapsin, CD99 (MIC2 protein), and FLI-1, prompting an initial diagnosis of Ewing sarcoma/primitive neuroectodermal tumor. However, a diagnosis of desmoplastic small round cell tumor was rendered after the detection by cytogenetic analysis of the reciprocal chromosomal translocation, t(11;22)(p13;q12), which is uniquely associated with this tumor. This is the first documented instance of desmoplastic small round cell tumor arising in bone.

Bone Neoplasms↗

Heat-accelerated fixation and rapid dissection of the pediatric brain at autopsy: a pragmatic approach to the difficulties of organ retention.

We investigated whether it is possible to accelerate the examination of a pediatric brain at autopsy and thus facilitate its return to the body before a funeral without compromising the quality of the neuropathologic examination. Accelerated fixation and next-day dissection of the brain was performed in selected cases over a 2-year period by using a microwave histologic tissue processor (MicroMed T/T MEGA, Milestone, Sorisole, Italy). Direct comparison of the histologic appearance and immunohistochemical reactivity of 2 cases, 1 fixed by conventional methods and 1 fixed with the accelerated method, was performed in a blinded fashion by a specialist neuropathologist. Examination of rapidly fixed brain by conventional thin coronal sections was readily achieved. There was no appreciable difference between tissue sections stained with hematoxylin and eosin and prepared from conventional formalin-fixed cortical and cerebellar brain tissue and that fixed by rapid heat acceleration. Immunocytochemical studies were not adversely affected by the accelerated heat-fixation process of tissue. Heat-accelerated fixation is a potential method of speeding up the examination of the brain at autopsy without unduly compromising the quality of the neuropathologic examination.

Adolescent↗

Perianal rhabdomyosarcoma presenting as a perirectal abscess: A report of 11 cases.

BACKGROUND PURPOSE: The organs and soft tissues of the pelvis are some of the most common primary sites for rhabdomyosarcoma (RMS) in children and adolescents. In most cases a mass is detectable on clinical examination, and the initial concern is focused on the possibility of a neoplasm. The current report concerns 11 patients, each presented with a painful perineal-perianal mass suggesting an abscess to the extent that each one of these patients was treated initially with antibiotics or incision and drainage for several weeks to months before the pathologic diagnosis of RMS was established. METHODS: The authors reviewed the clinical histories of all patients with perirectal/perianal RMS from their respective institutions to identify cases in which the initial clinical diagnosis or impression was that of a perirectal abscess. Pathologic material was reviewed in all cases. RESULTS: Eleven patients, 7 of whom were girls, ranged in age from 1 to 16 years at diagnosis (median age, 14 years). Fever accompanied the clinical presentation in 2 patients. None of the patients had a past medical history of illness that may have predisposed them to a perirectal abscess, although one patient had a family history of inflammatory bowel disease. Duration of symptoms ranged from 1 month to 1 year (mean, 4.6 months). Each patient presented with a tender perianal/perineal nodule or mass. Inguinal adenopathy was present in 6 patients at diagnosis. White blood cell counts ranged from 6,600/mm(3) to 24,500/mm(3). LDH levels ranged from 414 to 3,432 U/L. The average time from presentation to pathologic diagnosis of RMS was 2.1 months. Nine of the 11 cases showed an alveolar pattern. All were high-stage disease. Of 7 patients with follow-up longer than 1 year, 2 (29%) are alive without disease. CONCLUSION: This report presents the need to consider the possibility of a malignant neoplasm, in this case RMS, in a child or adolescent with a putative perirectal abscess that fails to respond in the expected manner to incision and drainage and antibiotic therapy.

Abscess↗

Multifocal infantile myofibromatosis and generalized fibromuscular dysplasia in a child: evidence for a common pathologic process?

Infantile myofibromatosis (IM) is a condition characterized by the formation of spindle cell tumors of skin, soft tissue, and viscera. Although small vessel involvement by the process is a frequently identified and indeed diagnostically useful histological finding, involvement of large vessels is not widely reported. Fibromuscular dysplasia (FMD) is a noninflammatory arteriopathy characterized by intimal, medial, and/or adventitial fibroplasias leading to luminal compromise and aneurysm formation. Although venous disease has been reported, involvement of arterioles and viscera has not been identified. We report a patient in whom IM was diagnosed, on the basis of multiple soft tissue tumors present from birth, who subsequently developed generalized and ultimately fatal FMD. These two conditions exhibit overlapping pathologic features, including pronounced intimal fibroplasia. Their occurrence in a single individual may provide insights into the pathogenesis of both conditions, suggesting that they represent part of the same spectrum of vascular myofibroblastic proliferations.

Child, Preschool↗