Duodenal Xanthoma: From Specks to Obstruction.

Xanthomas within the gastrointestinal tract occur secondary to a mucosal insult. When enough cells accumulate, their appearance can range from small nodules studding the intestinal mucosa to bandlike infiltrations to pseudotumor-like masses within the intestine with fibrosis and inflammation resembling malignancy. When large enough, they can produce symptoms of obstruction such as vomiting, abdominal pain, distention, and dysmotility. This case demonstrates the epidemiology, clinical presentation, diagnosis, and treatment of duodenal xanthomas.

Injection site pseudosarcoma in piriformis syndrome.

AIMS: Pseudosarcomatous reactive myofibroblastic proliferations have been described following surgery or trauma at a variety of anatomical sites. These types of reactions have not been previously described at injection sites. Here we evaluated prevalence, morphologic patterns and clinical resolution of such lesions. METHODS AND RESULTS: We analyzed 266 surgical resection specimens obtained during the definitive treatment of piriformis syndrome. Three cases showed exuberant reactive fibroblastic/myofibroblastic intramuscular proliferations, mimicking a sarcoma. In all three cases the surgeries were found to be preceded by local injections of cortisone and bupivacaine. Clinical follow-up revealed no uncontrolled growth. CONCLUSIONS: As the clinical history of injections is often not provided, it is important to be aware of this pitfall when reviewing skeletal muscle resections for entrapment syndromes.

The utility of PAX-2 and renal cell carcinoma marker immunohistochemistry in distinguishing papillary renal cell carcinoma from nonrenal cell neoplasms with papillary features.

PAX-2, a homeogene expressed during kidney development, has been studied as a marker of renal origin in both primary and metastatic clear cell renal cell carcinoma (RCC), but not in papillary neoplasms or in comparison with RCC marker (RCCma). We studied immunohistochemical expression of PAX-2 and RCCma in 24 papillary RCC (PRCC) and 66 nonrenal cell papillary neoplasms (NRCPN) from a variety of organs. Of the PRCC, 16/24 (67%) were positive for PAX-2; 23/24 (96%) were positive for RCCma. Of the NRCPN, 9/66 (14%) is positive for PAX-2 [4/10 (40%) ovarian papillary serous carcinomas, 5/9 (56%) uterine papillary serous carcinomas]; RCCma was positive in 28/66 (42%), including 9/9 (100%) papillary thyroid carcinomas, 8/10 (80%) ovarian papillary serous carcinomas, 4/9 (44%) uterine papillary serous carcinomas, 1/10 (10%) papillary urothelial carcinomas, 1/2 (50%) intraductal papillary mucinous carcinomas of the pancreas, 3/3 (100%) choroid plexus papillomas, 1/1 (100%) pituitary adenoma with papillary features, and 1/2 (50%) lung adenocarcinomas with papillary features. The sensitivity of PAX-2+/RCCma+ immunophenotype for PRCC was 58% with a specificity of 54%. There is significant overlap between the expressions of these markers in PRCC and NRCPN; however, the positivity of RCCma and/or PAX-2 is 100% sensitive for PRCC and may prove useful in the initial work up of metastases of unknown primary. PAX-2 and RCCma immunohistochemistry should be interpreted with caution in papillary neoplasms, with particular attention to the possibility of ovarian and uterine papillary serous carcinomas, which can express both PAX-2 and RCCma.

Lack of HER2 overexpression and amplification in small intestinal adenocarcinoma.

HER2 overexpression and amplification have been studied as a therapeutic and prognostic target in a number of human cancers, including esophageal, gastric, and colorectal adenocarcinomas. However, HER2 status has not been well investigated in primary small intestinal adenocarcinoma, probably because of its rarity. In this study, we conducted immunohistochemical analysis and fluorescence in situ hybridization (FISH) for HER2 on 49 primary nonampullar small intestinal adenocarcinomas. The results showed a complete lack of HER2 protein expression in 47 cases (96%) by immunohistochemical analysis. Only 2 cases (4%) showed a 1+ staining pattern. No tumors exhibited 2+ or 3+ HER2 immunoreactivity. By FISH, none of the tumors, including those with 1+ HER2 immunoreactivity, exhibited HER2 gene amplification. These observations demonstrate that HER2 protein overexpression and gene amplification are infrequent events, if they occur at all, in small intestinal adenocarcinoma. Thus, routine immunohistochemical and/or FISH testing for HER2 for potential targeted anti-HER2 therapy may not be beneficial for patients with primary small intestinal adenocarcinoma.

The utility of PAX-2 in distinguishing metastatic clear cell renal cell carcinoma from its morphologic mimics: an immunohistochemical study with comparison to renal cell carcinoma marker.

PAX-2 is a homeogene expressed during kidney development. Although immunohistochemical expression of PAX-2 has been described in a variety of primary renal cell carcinoma (RCC) subtypes and in metastatic RCC, its specificity as a marker of renal lineage in a metastatic setting has not been fully evaluated. In addition, its utility has not been directly compared with the most widely used antibody in this setting, renal cell carcinoma marker (RCCma). We studied PAX-2 expression in metastatic clear cell renal cell carcinoma (CC-RCC) and in a variety of nonrenal neoplasms with clear cytoplasm that may potentially mimic CC-RCC. Archival material from 27 CC-RCCs metastatic to various organs and 50 close morphologic mimics of CC-RCC were retrieved. Immunohistochemistry with PAX-2 and RCCmapi antibodies was performed on each case. Nuclear staining (PAX-2) or membranous staining (RCCma) was scored semiquantitatively. Twenty-three of 27 (85%) metastatic CC-RCCs showed nuclear immunoreactivity for PAX-2, whereas RCCma reactivity was found in 19 of 27 (70%). The immunoprofiles of the metastatic CC-RCC were PAX-2+/RCCma+: 19 of 27 (70%), PAX-2+/RCCma-: 5 of 27 (19%), PAX-2-/RCCma+: 2 of 27 (7%), and PAX-2-/RCCma-: 1 of 27 (4%). Five of the 50 mimics of CC-RCC (10%) had at least focal nuclear reactivity with PAX-2, including 1 of 3 parathyroid carcinomas (33%), 3 of 7 clear cell carcinomas of the ovary (43%), and the 1 clear cell papillary cystadenoma of the epididymis. Membranous RCCma reactivity was identified in 26 of the 50 mimics (52%). We conclude that PAX-2 is a useful marker for distinguishing metastatic CC-RCC from its potential morphologic mimics, but caution must be used in certain differential diagnostic settings where nonrenal tumors such as parathyroid carcinoma, ovarian clear cell carcinoma, and clear cell papillary cystadenoma of the epididymis were shown to express both PAX-2 and RCCma.

Androgens regulate the sexually dimorphic production of co-contained galanin and cholecystokinin in lumbar laminae VII and X neurons.

A population of rat lumbar laminae VII and X putative spinothalamic (STT) neurons that co-contain cholecystokinin-8 (CCK) and galanin (GAL) are sexually dimorphic. Males have a significantly greater number of these neurons, as well as having greater optical densities for both neuropeptides than females. Optical densities for GAL and CCK immunoreactivities in these lumbar neurons in rats that have the testicular feminization mutation (Tfm) are not significantly different from females; however, the number of these lumbar neurons in Tfm rats is significantly smaller than in females. These data suggest that androgens, as well as functional androgen receptors (that Tfm rats lack), are necessary for the establishment of these sexual dimorphisms. Functionally, these CCK- and GAL-containing neurons in the deep lumbar laminae may contribute to the establishment of known sex differences in the affective component of somatic and visceral nociception, as well as the sexually dimorphic nature of some pelvic diseases, e.g., irritable bowel syndrome or cystitis.