Simultaneous occurrence of follicular and papillary thyroid carcinomas in same thyroid lobe: A case series of six patients from Qatar

Background: Papillary thyroid carcinoma (PTC) and follicular thyroid carcinoma (FTC) are the first and second most common thyroid cancers comprising about 85% and 10% of all thyroid cancers. Simultaneous occurrence of medullary and papillary thyroid cancer has been reported with various presentations, but simultaneous occurrence of FTC in addition to PTC as differentiated cancers, is an unusual event that is rarely reported. Presentation of cases: We report our experience of six rare cases of synchronous coexistence of FTC and PTC with unique features. Case 1 is 31 old Egyptian female. Case 2 is a 61 year old Sudanese male. Case 3 is a 59 year old Sudanese male. Case 4 is a 56 years old Indian female. Case 5 is a 35 years old Filipina female. Case 6 is a 52 years old Qatari female. The six cases are special in their co-occurrence of two thyroid carcinoma, consisting of histologic features of follicular thyroid carcinomas, and classical papillary thyroid carcinoma, possibly the first case series of simultaneous occurrence of these two types of thyroid cancer in the Middle East and North Africa Region. Conclusions: We present rare cases of concurrent FTC and PTC. These six cases add more data highlighting the coincidental simultaneous coexistence of FTC and PTC. Endocrinologists and pathologists should be aware of and vigilant to this variety.