Endocrine Abstracts

Subcutaneous lipomas (SL) are the most common benign mesenchymal tumors with an estimated prevalence of 1%. They usually appear single, between 50–60 years of age, without gender differences. However, multiple lipomatosis (ML) occurs in 5–10% of patients, more frequently in men and almost 30% of them have family history of ML. Cytogenetic abnormalities are found in 50–80% of cases (at 12q15) and the presence of an underlying mitochondrial dysfunction has been suggested. Up to this date, there are no reports of SL/ML prevalence in patients with differentiated thyroid cancer (DTC). We have reviewed 240 patients with DTC, identified those with SL/ML and compared their features with those of the whole group. Among 194 women and 46 men (19%) with DTC, being 5% Hürthle cell carcinomas (HCC), we found 15 patients, 9 women and 6 men (40%), with ML mainly in arms, back and legs. Twelve of them (80%) referred appearance of ML in several members of their families at an early age. In the ML group there were 5 HCC (33%) (4 mixed with areas of multicentric papillary thyroid microcarcinoma), 1 multicentric mixed papillary-follicular carcinoma and 9 papillary (1 diffuse sclerosing variant, 2 microcarcinomas and 4 multicentric). Four men had suffered nonthyroid cancer (NTC): 1 seminoma, 2 melanomas and 1 colon cancer. Eleven patients had first-degree relatives with NTC mostly lung, breast and liver. Only 2 cases remained free of DTC. In our series the prevalence of ML is significantly higher than that of the general population with an increased frequency of familiar forms. When compared to the whole DTC group, ML is significantly associated with a higher rate of men, HCC, mixed forms, multicentricity and less probability of remaining free of disease (all P<0.001). Based on our findings ML could be considered a new bad prognostic marker in DTC.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector