Endocrine Abstracts

Background: Insular carcinoma of the thyroid is an extremely rare tumor (4% of cases) with a poor prognosis and an intermediate malignancy between differentiated and anaplastic cancers. The aim of this study was to define the particular points of this cancer by studying its diagnostic and prognostic aspects.

Materiel et methods: Retrospective study was conducted in Endocrinology and diabetology department of Ibn Rochd University Hospital of Casablanca, including 14patients followed for insular thyroid carcinoma between 1986 and 2017 among all thyroid carcinomas (614 patients)

Results: Insular carcinoma prevalence was 2%. Mean age was 56 (18-71)years. Reason for consultation was goiter in 9 patients and an isolated nodule in 5 patients. All patients had undergone total thyroidectomy with lymphnode dissection. Iratherapy (100 mci) was performed in all patients. Insular carcinoma represented the total tumor in 3 cases, or was associated with a well-differentiated follicular (3 cases) or papillary (8 cases) contingent. The mean size tumor was 4 cm (2–8 cm). Histological stages (pTNM) wereT2 (9 cases) T3 (3 cases) T4 (2 cases) N0 (10 cases) N1 (4 cases). A recurrence was found in 2 patients (locoregional recurrence and bone metastasis) with a delay of 28 months. Predictors of poor prognosis were age, large size, multifocality, and capsule invasion (P<0.01).

Conclusion: Our results highlight the rarity of insular carcinoma with a potential severity (pTNM stage, frequency of recurrence).