Immunohistochemistry of small round-cell tumors.

The term "small round-cell tumor" describes a group of highly aggressive malignant tumors composed of relatively small and monotonous undifferentiated cells with high nuclear to cytoplasmic ratios. This group includes Ewing's sarcoma (ES), peripheral neuroepithelioma (aka, primitive neuroectodermal tumor or extraskeletal ES), peripheral neuroblastoma ("classic-type"), rhabdomyosarcoma, desmoplastic small round-cell tumor, lymphoma, leukemia, small-cell osteosarcoma, small-cell carcinoma (either undifferentiated or neuroendocrine), olfactory neuroblastoma, cutaneous neuroendocrine carcinoma (aka, Merkel-cell carcinoma), small-cell melanoma, and mesenchymal chondrosarcoma. Their clinical presentations often overlap, thus making a definitive diagnosis problematic in some cases. Yet, a clear understanding of their clinicopathologic features usually allows for a confident diagnosis, especially if immunohistochemistry is used. The following is a review of the immunohistochemistry of this small round-cell tumor group.

Nemaline rods in canine myopathies: 4 case reports and literature review.

The diagnosis of nemaline rod myopathy (NM) is based on the presence of numerous pathognomonic rods within a fresh frozen muscle biopsy specimen. Three forms of congenital NM have been described in humans, and rods have been found to occur in various other conditions. A similar myopathy was described in 1986 in a family of cats. In this report, we describe a case of congenital NM in a 10-month-old Border Collie, an adult-onset NM in an 11-year-old Schipperke, and 2 acquired myopathies with nemaline rods in adult dogs associated with hypothyroidism and Cushing's syndrome. Common clinical features included exercise intolerance, abnormal electromyography, and the presence of nemaline rods in fresh, frozen, and glutaraldehyde-fixed biopsies from proximal appendicular limb muscles. Staining of cryostat sections of muscle biopsy specimens by the modified Gomori trichrome technique disclosed numerous rod bodies that were localized to type 1 fibers by the histochemical adenosine triphosphatase reaction. Accumulation of rods also was demonstrated by electron microscopy in 2 of the cases with localized enlargement and streaming of Z lines. Documentation of NM in a young Border Collie and the adult-onset form in the Schipperke alerts clinicians to the existence of this disorder in these breeds.

Organized thrombus in left main coronary artery in hypoplastic left heart syndrome.

A neonate is reported in whom, during Norwood stage I correction for hypoplastic left heart syndrome with mitral stenosis, an organized thrombus was found to protrude from the left coronary ostium into the aortic root. With ventricular assist device support the patient survived despite severe left ventricular ischemia. The presumed origin of the thrombus is from left ventriculocoronary arterial connections that serve to decompress the blind left ventricular cavity.

Ureteric obstruction secondary to endometriosis. Report of three cases with a review of the literature.

Three cases of endometriosis are presented. In one patient bilateral obstruction was noted; in a second patient bilaterally enlarged kidneys with unilateral obstruction were found and in the third patient only unilateral obstruction was defined. Intrinsic ureteric obstruction and bilateral obstruction, both rare findings, are described in this report. The diagnosis, evaluation and management of these patients are discussed.

Neurological complications of laparoscopy.

PIP: 2 cases of severe cerebral dysfunction after laparoscopy are reported and possible mechanisms of damage are discussed. The first case was 20 years old, and experienced a cardiopulmonary arrest during elective laparoscopy, rendering a once effervescent woman unemployable and without spontaneity. Case 2 was 39 years old and became apneic and hypotensive, and had a cardiac arrest during laparoscopy. 18 months later she remains bedridden with some grasp reflexes. 2 possible mechanisms are considered. The first is that of gas infiltration into the venous system; the second possibility is hypoxia secondary to cardiac arrest. The cardiac arrest may be anesthesia-related or may be accentuated by the Trendelenburg position. Once cerebral insult occurs following hypotension, supportive care includes massive doses of steroids, judicious use of fluids, and prevention of medical complications of coma. However, once a cerebral event has occurred, prognosis is the same as after other diffuse cerebral insults to patients of similar age.^ieng