Cohexisting Medullary and Papillary Thyroid Cancer

Purpose: Papillary thyroid carcinomas (PTCs) and medullary thyroid carcinomas (MTCs) have always been considered different in terms of their incidence rates, cell origins, and histopathological features. Simultaneous occurrence of both disease entities is very rare. Methods: We describe a series of cases with simultaneous MTC and PTC occurrences in the thyroid gland. Results: From 2,897 patients (mean age, 49.2±12.5; 81% women) who underwent thyroidectomy for cancer between 2000 and 2015, we reviewed 11 cases of simultaneous occurrence of MTCs and PTCs. Multifocal PTC with simultaneous MTC was detected in 5 of the 11 cases (45%). Of these PTC patients, 2 had 2 foci, 2 had 3 foci, and 1 had 4 foci. There was 1 case of multifocal MTC with solitary PTC. One patient presented with “composite thyroid carcinoma” with mixed features of MTCs and PTCs. Eight patients (72%) presented an association with diffuse lymphocytic thyroiditis. The sizes of the tumors were 1.95±0.23 cm vs. 1.20±0.20 cm for PTCs and MTCs, respectively (P=0.531). The prevalence of extrathyroidal extension was 33.1% vs. 30.2% for PTCs and MTCs, respectively (P=0.282). All patients underwent total thyroidectomy and central neck node dissection. Radio iodine was delivered to 44% of patients. Follow-up review revealed 9 disease-free patients and 1 with local neck recurrence, while 1 patient died due to non-thyroid reasons. Conclusion: There are only 30 reports describing a total of 50 cases in the English literature regarding concurrent PTC and MTC in the same gland. This study represents one of the largest case series. Whether the incidence of another cancer in these patients is coincidental, or due to the possible activation of a common tumorigenic pathway for both follicular and parafollicular thyroid cells, remains to be elucidated

The effects of Δ9-tetrahydrocannabinol on the dopamine system

Δ(9)-tetrahydrocannabinol (THC), the main psychoactive ingredient in cannabis, is a pressing concern to global mental health. Patterns of use are changing drastically due to legalisation, availability of synthetic analogues (‘spice’), cannavaping and aggrandizements in the purported therapeutic effects of cannabis. Many of THC’s reinforcing effects are mediated by the dopamine system. Due to complex cannabinoid-dopamine interactions there is conflicting evidence from human and animal research fields. Acute THC causes increased dopamine release and neuron activity, whilst long-term use is associated with blunting of the dopamine system. Future research must examine the long-term and developmental dopaminergic effects of the drug