Collision of desmoplastic-neurotropic melanoma and squamous cell carcinoma on the lip.

We report on a case of the collision of a desmoplastic-neurotropic melanoma and a squamous cell carcinoma on the lip. A 46-year-old male developed a multifocal infiltrative squamous cell carcinoma of the lower lip, which also showed sparse melanocyte atypia within the epidermis and an extensive spindle cell proliferation within the dermis, subcutaneous tissues and nerves. An immunohistochemical panel showed that the spindle cells were melanocytes, not derived from the squamous cell carcinoma.

Paraganglioma-Like Adenomas of the Thyroid (PLAT): Incidental Lesions with Unusual Features in a Patient with Nodular Goiter.

We discovered two well-demarcated nodules incidentally in a thyroid removed because of a nodular goiter. Histologically, the nodules showed a pattern of paraganglioma or so-called paraganglioma-like adenoma of the thyroid (PLAT), with lobules of polygonal and oval cells in a vascular stroma, but the immunohistochemical markers typical of paraganglioma, including chromogranin, synaptophysin, Leu 7 and 5-100, and thyroglobulin, characteristic of PLAT, were negative in the tumor cells. C-cell markers calcitonin and somatostatin were also negative.