Localized Lichen Myxedematosus With Plasma Cell Light Chain Restriction: Is It the Exception or the Rule?

Lichen myxedematosus is a chronic cutaneous mucinosis that can present on a spectrum from localized cutaneous lesions to systemic disease of scleromyxedema. The clinical presentation of localized cutaneous lichen myxedematosus is waxy lichenoid papules, nodules, and/or plaques that have histopathologic findings of mucin deposition and a variable degree of fibroblast proliferation. There is an absence of serum paraproteins, and there are no other systemic causes of cutaneous mucinosis such as thyroid disease. The pathogenesis of lichen myxedematosus is unknown. We report 3 cases of localized cutaneous lichen myxedematosus with a light chain-restricted plasmacytic component by in situ hybridization. Our findings deliver an insight for disease pathogenesis and highlight for the first time, the significance of plasma cells in lesions of localized cutaneous lichen myxedematosus. We suggest that plasma cell light chain restriction could represent a clue to distinguish localized cutaneous disease from systemic disease.

Multiple low-grade sarcomas of fibroblastic type in the setting of HIV and acquired epidermodysplasia verruciformis.

A 46-year-old white male with a history of HIV (CD4 245), acquired epidermodysplasia verruciformis, anal carcinoma in situ, hepatitis B and C presented with 3 asymptomatic, nontender, firm pink/skin-colored nodules involving the arm, left lateral leg, and right third finger. One year later, he developed a similar lesion on his right medial lower leg. Excisional biopsy of one of the lesions showed an atypical spindle cell neoplasm of the dermis compatible with a low-grade sarcoma of fibroblastic origin. Testing for human herpes virus-8, 23 human papillomavirus types, Epstein-Barr virus, and FUS fusion protein were negative. The patient underwent diagnostic imaging with computed tomography scans of the chest, abdomen, and pelvis along with positron emission tomography scan to ensure that there was no other occult primary tumor, all of which were negative. The lesions were excised and have not recurred with 3 years of follow-up. The best histopathologic term for these lesions is multiple low-grade sarcomas of fibroblastic phenotype. They have been proven to be nonaggressive, with little or no metastatic potential. This is a neoplastic process that has not been well defined in the literature. To our knowledge, there are no previous reports of these lesions occurring in multiple sites or in an HIV-positive patient.

Angiotropism of human melanoma: studies involving in transit and other cutaneous metastases and the chicken chorioallantoic membrane: implications for extravascular melanoma invasion and metastasis.

Melanoma cell migration along the outside of vessels has been termed "extravascular migratory metastasis" (EVMM), as distinct from intravascular dissemination. Previous studies in both human and experimental melanoma models have shown angiotropism of melanoma cells, suggesting EVMM. Our objectives are to study the mechanism of dissemination of human melanoma cells in the chick chorioallantoic membrane (CAM) and to compare the histopathology in the CAM with that of patients with in transit and other cutaneous melanoma metastases. Human and murine melanoma cells were inoculated onto the CAM and observed over a 10-day period for tumor dissemination. Both human melanoma specimens from 26 patients and melanoma cells growing on the CAM showed the presence of tumor cell angiotropism at the invasive front of the tumor and at some distance from the tumor mass. In addition, a clear progression of melanoma cells spreading on the CAM was observed along the abluminal surface of vessels, where they occupied a perivascular location. By day 10 after injection, small micrometastases had developed along vessels, in a pattern similar to that in transit and other cutaneous melanoma metastases. In addition, the results suggested that the number of micrometastases directly correlated with increasing tumor volume. Taken together, these data suggest that the CAM is a relevant model for studying tumor cell dissemination, and that EVMM may be a mechanism by which some melanoma cells spread to nearby and even distant sites.

Extramammary Paget's disease presenting on the face.

BACKGROUND: Extramammary Paget's disease is a rare neoplasm primarily affecting apocrine gland bearing skin. Although primarily affecting the anogenital area, the tumor also rarely appears in nonapocrine bearing skin and is referred as ectopic extramammary Paget's disease. OBJECTIVE: To our knowledge, we present only the second case of ectopic extramammary Paget's disease appearing on the face. METHODS: Using Mohs micrographic surgery, a rare case of ectopic extramammary Paget's disease on the face was treated in three stages. RESULTS: At 5 months there was no evidence of recurrence. CONCLUSION: Ectopic extramammary Paget's disease is a rare disease that can be effectively treated with Mohs micrographic surgery.