Primary small cell thyroid carcinoma combined with poorly differentiated thyroid carcinoma, evidence for a common origin: A case report

Abstract

Primary small cell thyroid carcinomas are extremely rare and there is still debate about their classification as a distinct disease entity. The present case report reports a small cell carcinoma (SCC) combined with poorly differentiated thyroid carcinoma (PDTC) in a 34 year old man. The tumor consisted of ~80% PDTC and ~20% SCC. The PDTC component was positive for cytokeratin and thyroid transcription factor-1 (TTF-1), and negative for calcitonin, chromogranin and synaptophysin. The SCC component was positive for synaptophysin and CD56, and negative for calcitonin, chromogranin and TTF-1. Seven months after thyroid surgery, two new lung nodules were detected. Histologically and immunohistochemically, the lung tumors were similar to the SCC component of the thyroid carcinoma. The mutational status of cancer-related genes was assessed using targeted next-generation sequencing in both the thyroid and lung, which identified similar genetic alterations. The histogenesis of SCC was evaluated through NGS analysis of the two cancer components.

The Long Journey towards Personalized Targeted Therapy in Poorly Differentiated Thyroid Carcinoma (PDTC): A Case Report and Systematic Review

“…In the majority of studies in our review, the extent of the poorly differentiated area was not reported, and a PDTC definition was decided to address this component. A large number of patients with PDTC reviewed herein presented with locally advanced disease (T3 or T4, extrathyroidal extension, and nodal involvement) [ 40 , 44 , 46 , 47 , 49 , 50 , 51 , 54 , 55 , 57 , 58 , 60 , 61 , 62 , 64 , 67 , 68 , 69 , 70 , 71 , 73 , 74 , 75 , 76 , 77 , 78 , 80 , 81 , 82 , 83 , 84 , 85 , 86 , 87 , 88 , 90 , 91 , 92 , 94 , 97 , 98 , 99 , 100 , 101 , 102 , 107 , 108 , 109 , 111 , 112 , 113 , 114 , 115 , 116 ,…”

“…At present, there is no effective targeted chemotherapeutic regime for PDTC. Cisplatin/doxorubicin and carboplatin/paclitaxel are similar combinations that are used to modulate disease progression, and likewise, only a few of the revised studies used these schemes for select patients [ 42 , 57 , 60 , 78 , 97 , 114 , 119 ].…”

“…In the majority of studies in our review, the extent of the poorly differentiated area was not reported, and a PDTC definition was decided to address this component. A large number of patients with PDTC reviewed herein presented with locally advanced disease (T3 or T4, extrathyroidal extension, and nodal involvement) [40,44,46,47,[49][50][51]54,55,57,58,[60][61][62]64,[67][68][69][70][71][73][74][75][76][77][78][80][81][82][83][84][85][86][87][88][90][91][92]94,[97][98][99][100][101][102][107][108][109]…”