Diagnosis and Treatment of Merkel Cell Carcinoma in Specialized Dermatology Units: A Clinical Practice Guideline of the Spanish Academy of Dermatology and Venereology. / Carcinoma de células de Merkel: diagnóstico y tratamiento en atención especializada dermatológica. Guía de práctica clínica de la Academia Española de Dermatología y Venerología.

BACKGROUND AND OBJECTIVE: Merkel cell carcinoma is a rare, aggressive skin cancer that is managed in a great variety of ways. However, international clinical practice guidelines give only partial coverage to issues considered major problems.The recommendations presented here aim to provide Spanish dermatologists with a guide to improving disputed aspects of diagnosis, staging, and treatment of localized Merkel cell carcinomas. MATERIAL AND METHODS: The ADAPTE process was used. Members of the Spanish Group of Oncologic Dermatology and Surgery (GEDOC) with experience in treating Merkel cell carcinoma and interest in drafting these guidelines were selected. The group described the care process and listed the most important clinical questions. They then searched for guidelines and assessed them with the AGREE II (Appraisal of Guidelines for Research and Evaluation) tool. After consulting the guidelines for answers to their clinical questions, the group drafted the present statementand sent it for external review. RESULTS: The guidelines that scored highest in the AGREE II assessment step were the consensus-based interdisciplinary guideline of the European Association of Dermato-Oncology and the European Organization of Research and Treatment of Cancer, and those of the Comprehensive Cancer Network, the Alberta Health Services in Canada, the American Cancer Society, and the Cutaneous Oncology Group of the French Society of Dermatology. A total of 9 clinical questions were answered based on these guidelines. CONCLUSIONS: The guidelines presented here answer clinical questions that arise in routine practice. They can provide dermatologists with a starting point for decision-making, although available resources and patient preferences must always be borne in mind.

Persistent subcutaneous nodules in patients hyposensitized with aluminum-containing allergen extracts.

BACKGROUND: The development of persistent nodules that cause pain and itching at a vaccination or hyposensitization injection site is a rare event. These lesions have been mainly attributed to a hypersensitivity reaction to aluminum hydroxide, which is used as an absorbing agent in many vaccines and hyposensitization preparations. Patch tests with standard antigens and aluminum compounds and histopathologic and ultrastructural studies were performed on 10 patients with persistent subcutaneous nodules on the upper part of their arms after injection of aluminum-adsorbed dust and/or pollen extracts. OBSERVATIONS: The nodules appeared 1 month to 6.5 years after injections. The results of patch tests with 2% aluminum chloride were positive in five patients. Histopathologic examination revealed two different patterns: some biopsy specimens (from lesions of less than 9 months' duration) showed a pure foreign body histiocytic reaction characterized by extracellular amorphous dermal basophilic deposits with a histiocytic-macrophagic reaction; others showed a delayed hypersensitivity granulomatous reaction in association with an histiocytic foreign body response. The lesions were characterized by a unifocal or multifocal unencapsulated granulomatous reaction in the deep dermis and/or subcutaneous tissue. Eosinophilic necrotic areas surrounded by dense fibrous bands and a massive inflammatory infiltrate (lymphoid follicles, large histiocytic cells, abundant eosinophils, and some plasma cells) were observed. A granular basophilic material in extracellular spaces and within the cytoplasm of some histiocytes was also noted. Electron microscopic studies revealed intracytoplasmic and extracellular deposits of a fibrillar electron-dense material. CONCLUSIONS: Persistent subcutaneous nodules that develop after the administration of aluminum-containing preparations may show two characteristic histopathologic patterns. A pure histiocytic foreign body reaction was observed in early lesions, and a delayed hypersensitivity granulomatous reaction was seen in older lesions. No relationship between histopathologic pattern and patch test results was observed. Aluminum-free preparations should be used in patients in whom these nodules develop.