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This is a description of a patient with a juvenile melanoma occurring at the site of a BCG vaccination.

Paragangliomas rarely involve the cauda equina region. In this location, these tumors can show misleading morphological features such as trabecular or papillary growth patterns and variable expression of cytokeratins.We comparatively studied the immunohistochemical and ultrastructural patterns of 3 paragangliomas of the cauda equina (PCE) and of 8 paragangliomas from other sites.All the paragangliomas expressed neuroendocrine markers (neuron-specific enolase, chromogranin A, synaptophysin and neurofilament protein). In PCE, chief cells exhibited a strong positivity with a broad spectrum anti-cytokeratin antibody. The staining was diffuse in the cytoplasm or had a paranuclear dot-like disposition. In other sites, only one paraganglioma showed a focal expression of cytokeratins. At ultrastructural level, chief cells of PCE contained characteristic dense core granules and intermediate-sized filaments sometimes grouped in paranuclear whorls.The dual immunophenotype of PCE, paraganglionic and epithelial, must be recognized in order to distinguish these tumors from, for example, a metastasis of a neuroendocrine carcinoma. PCE are slow-growing tumors and have mostly a favorable prognosis after complete surgical excision.

Most hydatid cysts are found in the liver or lungs but occurrence in other locations is possible. The purpose of this report is to describe three cases involving cysts locate in the ovary, joint, and thyroid. Clinical findings associated with these uncommon locations were poorly specific and diagnosis required histological examination after surgical exploration. Imaging and serology were useful to differentiate hydatid cyst from benign or malignant tumor disease but often failed to achieve definitive differential diagnosis. Thorough investigation is necessary to rule out more common locations in the liver or lung. Continued surveillance is needed for early detection of recurrence. Preventive campaigns are necessary in endemic areas, such as Morocco.