Renal cell carcinoma marker (RCC-Ma) is specific for cutaneous metastasis of renal cell carcinoma.

BACKGROUND: Renal cell carcinoma marker (RCC-Ma) is a monoclonal antibody against a normal renal proximal tubule antigen. RCC-Ma expression is relatively specific for primary clear cell renal cell carcinoma. Its expression in cutaneous metastasis of renal cell carcinoma (MRCC) and other cutaneous clear cell lesions has not been studied. METHODS: One hundred and thirty-seven cutaneous clear cell lesions including eight xanthomas, 32 xanthelasmas, 25 xanthogranulomas, seven balloon cell nevi, six clear cell hidradenomas, 29 sebaceous adenomas, six sebaceous epitheliomas, eight sebaceous carcinomas, and 16 MRCC were examined using immunohistochemistry for the expression of RCC-Ma. RESULTS: RCC-Ma was expressed in 10 of 16 (62.5%) MRCC, all with greater than 20% of cell labeling. Of these, 4 of 10 (40%) labeled with a membranous pattern and 6 of 10 (60%) labeled with both a membranous and a cytoplasmic pattern. RCC expression was not seen in any of the other clear cell lesions (p < 0.001). Furthermore, lack of expression in each of the other diagnostic groups was significant when each group was compared with the MRCCs (p < 0.01 at least for each group). CONCLUSIONS: Our study demonstrates that RCC may be a valuable component of a panel of immunohistochemical markers when evaluating cutaneous clear cell lesions.

CD10 is expressed in cutaneous clear cell lesions of different histogenesis.

BACKGROUND: CD10, the Common Acute Lymphoblastic Leukemia Antigen, is a neutral endopeptidase commonly used as a marker of early B-cell differentiation in the classification of lymphomas. Neoplasms of other histogenesis may express CD10, including renal cell carcinoma. Renal cell carcinoma metastatic to the skin (MRCC) can simulate other more common clear cell lesions in which expression of CD10 has not been described. METHODS: Fifty-two cutaneous clear cell lesions including xanthomas (CX), xanthelasmas (XA), xanthogranulomas (XG), balloon cell nevi (BCN), nodular/clear cell hidradenomas (CCH), and MRCC were examined by immunohistochemistry for the expression of CD10, noting frequency and pattern of labeling. RESULTS: CD10 was expressed in 32/35 of the xanthomatous lesions (CX, XA, and XG), 3/3 MRCC, but only 2/8 BCN and 2/6 CCH. BCN and CCH expressed CD10 in fewer than 10% of the clear cells, whereas all MRCC and most xanthomatous lesions had labeling in greater than 10% (p < 0.001). Xanthomatous lesions exhibited a predominantly membranous pattern of labeling compared to the cytoplasmic pattern of MRCC (p < 0.025). CONCLUSIONS: Cutaneous clear cell lesions of different histogenesis express CD10, limiting its use as a specific diagnostic marker for MRCC. Among other clear cell lesions, however, BCN and CCH have a lower frequency of labeling than does MRCC, and xanthomatous lesions show a membranous pattern compared to the cytoplasmic pattern of MRCC, BCN, and CCH. This latter observation may be indicative of altered protein function or trafficking.

Lymphomatoid papulosis from childhood with anaplastic large-cell lymphoma of the small bowel.

Lymphomatoid papulosis (LyP) is a lymphoproliferative disorder that exists on a spectrum of diseases with cutaneous CD30+ anaplastic large-cell lymphoma (ALCL). Multiple treatment options are available, although none are curative. The typical age of onset for LyP is in the third and fourth decades, but it has been seen occasionally in children. Lymphomatoid papulosis is associated with primary cutaneous ALCL and other lymphoproliferative malignancies, but is rarely associated with extranodal systemic ALCL. A 43-year-old man developed lymphomatoid papulosis lesions at 3 years of age, which persisted into adulthood, and he later developed ALCL of the duodenum. Treatment with standard CHOP (cyclophosphamide/doxorubicin/vincristine/prednisolone) chemotherapy resulted in complete remission of his gastrointestinal lymphoma and temporary improvement of his skin lesions. However, the LyP relapsed and proved refractory to psoralen plus ultraviolet-A phototherapy, and was only temporarily and partially responsive to bexarotene and denileukin diftitox.

A review of the dermatologic manifestations of poxvirus infections.

Physicians need to be familiar with the presentation of poxvirus infections. The poxvirus infections that are common, such as MCV, are rarely serious; however, physicians need to understand them because they can be bothersome to patients and require reassurance and, if available, treatment. The more rare poxvirus infections, such as variola, need to be recognized because they are generally serious. It is important to consider that these infections can suggest underlying systemic disease, as in the case of severe, recalcitrant MCV infection, which may be indicative of HIV infection or another immunocompromised state.