Endocrine Abstracts

Lentigo malign melanoma corresponds to the main histological type of melanomas ‘in situ’, particularly affecting Caucasian elderly exposed chronically to the ultraviolet rays. The therapeutic course should be surgical, with careful resection of the tumor, allowing free and wide margins. Follicular thyroid carcinoma corresponds to the second most common histological type characterized as a well differentiated neoplasm. It presents markedly vascular dissemination, being rare lymph node involvemen. The degree of vascular extension determines the severity of the tumor, as well as if the variant is from Hurthle cells, which confers a higher risk prognosis. Both tumors have congruent mutations, especially BRAF, RAS family (K-RAS, N-RAS and H-RAS) and TERT as carcinogenesis mechanisms. Although rare in lentigo maligna melanoma, the presence of these markers should be suspected in patients who evolve with other malignant neoplasms, with similar genetic pathophysiology.

Case: A 62 years old female, caucasian, with no known comorbidities, sought medical assistance due to the growth of blackened macular lesion on the lower left lip. He had goiter on physical examination. The labial lesion was suspected of melanoma, being surgically resected. The anatomopathological result was compatible with lentigo maligno melanoma in situ, measuring 3.4×2.3×1.2 cm, with free lateral and deep surgical margins. Patient was submitted to total thyroidectomy with cervical emptying in November 2018, whose anatomopathological result was: granular follicular thyroid carcinoma variant of widely invasive, multifocal, right lobe, measuring 5 cm and 3.8 cm in the right lobe axis, with angiolymphatic infiltration and focally compromised surgical margins. Dermal and subcutaneous metastasis of the carcinoma, with the same histopathological characteristics.

Discussion: - This is an uncommon case with extensively invasive follicular carcinoma, with very aggressive behavior, diffusely affecting the lungs, and presenting metastases to the dermis and subcutaneous, these latter two sites being infrequent for metastatic involvement by thyroid tumors. The association with lentigo maligna melanoma, whose pathophysiology involves mutations in BRAF and RAS genes, may not be merely sporadic but associated with mutations in the same genes. The association of thyroid cancers with other malignant tumors has been described in the literature, being the breast, kidneys and skin the most common. In view of the aggressiveness of the patient’s thyroid tumor and the association with lentigo malign melanoma, the case report is important, allowing new lines of study between thyroid carcinomas and other related malignancies.