George K. Mutema

A case of intraepidermal Merkel cell carcinoma within squamous cell carcinoma in-situ: Merkel cell carcinoma in-situ?

We report a case of a 79-year-old Caucasian male who presented with a wrist lesion of combined intraepidermal Merkel cell carcinoma and squamous cell carcinoma in-situ. The two tumors were tightly admixed and distinct, and both were without any dermal or invasive components. No features of transition between the two tumors were seen. We suggest the term Merkel cell carcinoma in situ for tumors that demonstrate exclusive intraepidermal proliferation of neuroendocrine cells.

Colocalized granular cell tumor and infiltrating ductal carcinoma of the breast.

A 57-year-old woman presented with a 2-year history of a palpable mass in the upper inner quadrant of the right breast. A 1.1-cm, poorly circumscribed, firm tumor nodule was noted, consisting of 2 histologically distinct lesions in the same location, with some areas showing purely well-differentiated invasive ductal carcinoma and others composed of granular cell tumor. In 1 area, the 2 tumors collided and infiltrated each other. The invasive ductal carcinoma was admixed with ductal carcinoma in situ of solid and cribriform types. To our knowledge, this is the first case report demonstrating colocalization of these 2 neoplasms, which raises questions regarding causal relationship. We also review the literature on granular cell tumor of the breast.

Intraosseous schwannoma of the humerus

Abstract. Intraosseous schwannomas are rare benign neoplasms of the bone, of which fewer than 200 cases have been described in the world literature. These tumors are well-defined, lytic lesions, rarely associated with pathologic fracture. The mandible is the most frequently involved bone. We present only the third case of an intraosseous schwannoma involving the humerus.

Magmas expression in neoplastic human prostate.

Magmas, is a 13-kDa mitochondrial protein which is ubiquitously expressed in eukaryotic cells. It was identified as a granulocyte-macrophage-colony stimulating factor (GM-CSF) inducible gene in hematopoietic cells and has a key role in the transport of mitochondrial proteins in yeast. Because GM-CSF receptor levels are elevated in prostate cancer, Magmas expression was examined in normal and neoplastic tissue. Magmas protein levels were barely detectible in non-neoplastic prostate glands. Increased amounts were observed in some samples of intraepithelial neoplasia. Approximately one half of the adenocarcinoma samples examined had weak Magmas expression, while the remainder had intermediate to high levels. The increased Magmas observed in malignant tissue was a result of higher protein expression and not from changes in mitochondrial content. Interestingly, in some patients, the normal prostate tissue had more Magmas message than the malignant portion. The results indicated that Magmas expression in prostate cancer is heterogeneous and independent of clinical stage and Gleason score. Further studies are needed to determine if Magmas expression has prognostic significance in prostate cancer.

Developmental Expression of Magmas in Murine Tissues and Its Co-expression with the GM-CSF Receptor

Magmas is a protein that is involved in GM-CSF signaling in a myeloid cell line. Its precise role in the signal transduction process is unclear. To accurately characterize Magmas expression in a variety of cells, mouse embryos and adult murine tissues were analyzed for both mRNA and protein content. Magmas expression was detected as early as the day 6.5 embryo. The level of expression was developmentally regulated. During embryo-genesis, elevated Magmas was observed in several structures, including heart, liver, notochord, choroid plexus, cervical ganglion, and nasal mucosa. Muscle, pancreas, intestinal mucosa, and testes were among the adult tissues with high Magmas expression. Most cell types, including hepatocytes and skeletal, smooth, and cardiac myocytes, also expressed the GM-CSF receptor (GMR) but the relative tissue levels of GMR were not always proportional to Magmas. The expression patterns suggest that Magmas has a role in both developing and mature tissues.

Premature closure of foramen ovale and renal vein thrombosis in a stillborn twin homozygous for methylene tetrahydrofolate reductase gene polymorphism: a clinicopathologic case study.

Abstract Premature closure of the foramen ovale, 4-chamber cardiac hypertrophy, and renal vein/vena cava thrombosis were found at autopsy of a stillborn dizygotic twin at 36 weeks gestational age. Review of the original prenatal sonograms showed features suggestive of early closure of the foramen ovale. Homozygosity for the 5,10 methylene tetrahydrofolate reductase mutation was shown only in the affected twin after the parents were found to be heterozygous for the mutation. The difference in outcome of the twins following prenatal treatment with beta mimetics and corticosteroids for preterm labor may be related to the added susceptibility factor for thromboembolism associated with presumed hyperhomocysteinemia in the proband which was not shared by the surviving healthy twin. The role of premature closure of the foramen ovale and prenatal treatment are discussed but remain uncertain.

Numerical criteria for the diagnosis of placental chorangiosis using CD34 immunostaining

Summary Not only the pathogenesis and clinical significance of hypervascularity of chorionic villi remain unknown but also the diagnostic criteria thereof are occasionally difficult to apply, particularly in borderline cases and in the presence of congestion and increased extracellular matrix of the chorionic villi. Immunohistochemistry is a powerful method for highlighting details in tissue sections. We used CD34 immunostaining to mark vascular outlines in the chorionic villi in five placentae with chorangiosis diagnosed on H&E stained slides as compared to five control placentae without chorangiosis, matched for gestational age and clinical diagnosis. We have observed that CD34 immunostaining facilitates counting capillaries through increasing the number of identifiable chorionic vessels in placental sections. However, the number of villous vessels forms a continuum, both within one placenta and between placentae. Maintaining the H&E Altshulers numerical criteria of chorangiosis with CD34 immunostaining would increase the number of cases diagnosed as chorangiosis. Therefore, we propose the CD34 cutoff point of 20 vessels per chorionic villus as corresponding to the Altshulers H&E cutoff point of 10 vessels. Vascular density, as defined by H&E and CD34 counts, shows excellent correlation in placentae with normal villous vascularity, but poor correlation in placentae with increased branching of villous capillaries. In addition, cytotrophoblastic proliferation, as highlighted with monoclonal MIB-1 antibody, is not significantly different in chorangiotic and nonchorangiotic placentas.

Malignant mesenchymoma of the orbit: case report and review of the literature

OBJECTIVE Malignant mesenchymoma are rare tumors of the orbit. From 1961 using English-language literature, we present the sixth such case and the first case with three malignant components. DESIGN Interventional case report. METHODS The clinical presentation, workup, surgical treatment, and pathology of a case of malignant mesenchymoma of the orbit are presented. RESULTS Although very rare, these tumors should be in the differential diagnosis of any tumor of the orbit. The prognosis is unknown because of the lack of follow-up of reported patients. CONCLUSIONS This malignant orbital mesenchymoma, an entity not accepted by all pathologists, was more complex than cases previously reported in the English literature in demonstrating rhabdomyosarcomatous, chondrosarcomatous, and osteogenic differentiation.