Report of a case: primary mucinous carcinoma of the skin.

Primary mucinous carcinoma of the skin is an extremely rare adnexal tumor that is thought to originate from eccrine sweat glands. The neoplasm usually arises on the head and neck, with the most commonly involved area being the periorbital region. The tumor is typically a solitary, asymptomatic nodule, cyst, or ulcer that is slow growing with low metastatic potential. However, post-excisional local recurrence is common, affecting up to 36 percent of patients. Since primary mucinous carcinoma of the skin is such a rare neoplasm (fewer than 130 cases have been reported to date), a complete workup should be conducted to rule out other internal malignancies that may metastasize to the skin. We report a case of primary mucinous carcinoma of the skin, and discuss the clinical presentation, histology, treatment, course, and prognosis.

Nephrogenic fibrosing dermopathy in a patient with systemic lupus erythematosus and acute lupus nephritis.

Nephrogenic fibrosing dermopathy is a recently recognized skin disorder similar in appearance to scleromyxedema but without the systemic involvement. We describe a 14-year-old girl with new-onset systemic lupus erythematosus and acute lupus nephritis who developed on the lower extremities confluent hyperpigmented, woody, indurated plaques that contained groups of coalescing erythematous papules. Nephrogenic fibrosing dermopathy was diagnosed histologically. Possible etiologies are discussed.

p75(NGFR) immunostaining for the detection of perineural invasion by cutaneous squamous cell carcinoma.

BACKGROUND: Perineural invasion (PNI) in cutaneous squamous cell carcinoma (CSCC) may portend a poor prognosis for patients. p75NGFR (nerve growth factor receptor) is part of a membrane receptor complex that binds nerve growth factor. Its use for detecting PNI in CSCC in comparison with S-100 immunohistochemical staining has not been explored. OBJECTIVE: To determine whether detection of PNI may be improved by staining with p75NGFR compared with hematoxylin and eosin (H&E) and S-100. METHODS: Thirty-four cases of CSCC were retrospectively evaluated for the presence of PNI using standard H&E, as well as S-100 and p75NGFR immunohistochemical stains. Staining intensity was correlated to the presence or absence of PNI and tumor differentiation. RESULTS: The results showed a positive correlation between staining intensity and the presence of PNI detected by p75NGFR (p=.04). Using p75NGFR allowed for the detection of seven cases of PNI not detected by H&E alone. Five of these cases were detected by S-100, with two cases seen by p75NGFR only. Six cases of PNI were detected using S-100 not seen on H&E, with one case also not seen using p75NGFR. CONCLUSION: p75NGFR immunostaining increased detection of PNI compared with H&E. p75NGFR could serve as an alternative to S-100 in the detection of PNI or as part of an immunostaining panel for PNI detection.

Loss of mismatch repair proteins in sebaceous gland tumors.

BACKGROUND: Sebaceous gland neoplasms are rare tumors that are associated with visceral malignancies in patients with Muir-Torre syndrome (MTS). The majority of the MTS-associated tumors reveal mutations in DNA mismatch repair (MMR) genes (most often hMSH-2 and hMLH-1) and microsatellite instability. The sebaceous gland lesions in patients with MTS can often precede or occur concurrently with the visceral neoplasms. The early recognition of those lesions and their differentiation from sporadic sebaceous gland tumors are critical for proper patient management. Here we investigate the MMR gene expression in a variety of sebaceous gland tumors, with or without associated visceral malignancy. METHODS: We studied the expressions of hMLH-1 and hMSH-2 in 10 consecutive sebaceous hyperplasias, 10 sebaceus nevi, 12 sebaceous adenomas, seven sebaceous carcinomas and the adjacent normal sebaceous glands using immunohistochemistry and paraffin-embedded sections. RESULTS: The normal sebaceous glands and the glands of all the sebaceus nevi were positive for hMLH-1 and hMSH-2. Loss of hMSH-2 expression was found in 1/10 (10%) sebaceous hyperplasias, 3/12 (25.0%) sebaceous adenomas, and 2/7 (28.6%) sebaceous carcinomas. Loss of hMLH-1 expression was seen in 1/10 (10%) hyperplasias, 3/12 (25.0%) adenomas, and 1/7 (14.3%) carcinomas. No concurrent loss of both hMLH-1 and hMSH-2 was observed. Loss of MMR (either hMLH-1 or hMSH-2) was detected in 80% of the benign sebaceous lesions associated with malignancy. In comparison, only 23% of sebaceous lesions not associated with malignancy showed loss of MMR proteins. No loss of hMSH-2 protein was found in the visceral cancer in one patient with hMSH-2-negative sebaceous adenoma. CONCLUSIONS: Our results confirm the previous reports of alterations of mismatch repair genes in the sebaceous neoplasms of patients with MTS. However, we showed that those changes also occur early at the stage of sebaceous hyperplasia, even in the absence of a visceral malignancy. This indicates the importance of the abnormal DNA mismatch repair in the progression of this disease.

Experimental nonsurgical tattoo removal in a guinea pig model with topical imiquimod and tretinoin.

BACKGROUND: Tattoo removal is a common request in dermatologic surgery practices. Conventional tattoo removal modalities consist of mechanical, chemical, and thermal methods, but these interventions may result in undesirable dermal damage, disfiguring scars, and pigmentary changes. OBJECTIVE: To evaluate the efficacy of topical imiquimod and tretinoin for the removal of tattoos in a guinea pig model. METHODS: Five albino guinea pigs (A-E) were tattooed with black, red, green, and yellow. Beginning 6 hours after tattooing, A received no treatment, B was treated with petrolatum, C had imiquimod cream alternating with tretinoin gel, D had imiquimod cream alone, and E received tretinoin gel alone. The animals were treated for 7 days. Biopsies of the tattoos were taken at 6 hours, 7 days, and 28 days. RESULTS: Control guinea pig B had normal-appearing tattoos with consistent histopathology on day 28. Guinea pig D, treated with imiquimod cream clinically, had no visible tattoo, consistent with greatly diminished or no dye evident on histopathology. Guinea pig E, treated with tretinoin gel, and guinea pig C, treated with combination tretinoin gel and imiquimod cream, had faded tattoos and moderate clearance of pigment on histopathology. CONCLUSION: In the guinea pig, the use of imiquimod was successful as a nonsurgical method of acute-phase tattoo removal, but was associated with fibrosis and the loss of dermal appendages.