Primary pulmonary adenocarcinoma mimicking papillary thyroid carcinoma

Ya-Zhen Zhu,Wei-Ping Li,Hai-Feng Yang,Hong-Guang Zhu,Zhi-Yuan Wang,Qing-Lian He,Guang-Juan Zheng

doi:10.1186/1749-8090-8-131

Abstract

We herein reported a primary pulmonary papillary carcinoma with colloid-like luminal content in the glandular cavity and classic nuclear features such as pseudo-inclusions, intranuclear grooves in the tumor cell nuclei and ground glass nuclei which closely mimics papillary thyroid carcinoma. Meanwhile, lymph node in the left pulmonary hilum was involved and showed similar features to the primary pulmonary papillary carcinoma. This specific histopathological presentation caused a diagnostic dilemma.The patient didn’t show previous concomitant or subsequent evidence of a thyroid tumor. Immunohistochemistry further confirmed pulmonary origin and excluded a metastasis from the thyroid, as it was thyroglobulin negative, thyroid transcription factor 1 and surfactant apoprotein A positive, which was consistent with the imageology and history.Based on the above features, the diagnosis of primary pulmonary papillary carcinoma was confirmed. Understanding the existence of papillary thyroid carcinoma-like pulmonary papillary carcinoma will avoid misdiagnosis or unnecessary clinical and radiologic investigations in future.

Highlights

Adenocarcinoma is the most common histologic subtype of lung cancer in most countries
Papillary thyroid carcinoma-like pulmonary papillary carcinoma has not yet been recognized as a histopathological variant. One such case has been previously reported that metastasis to the thyroid from lung adenocarcinoma could masquerade as thyroid carcinoma on fine needle aspiration (FNA) cytology [3], and that was a diagnostic pitfall in considering a metastasis tumor as a primary
The current study reported an example of pulmonary papillary adenocarcinoma with colloid-like luminal content showed scalloped borders in the glandular cavity and classic nuclear features such as pseudoinclusions, intranuclear grooves in the tumor cell nuclei, ground glass nuclei which closely mimics papillary thyroid carcinoma

Summary

Background

Adenocarcinoma is the most common histologic subtype of lung cancer in most countries. In the tissue of metastasis lymph node in the left pulmonary hilum, the tumor presented well-differentiated branching papillae that mimicked papillary thyroid carcinoma with a lot of colloid-like luminal content showed scalloped borders in the glandular cavity, the nuclei of tumor cells contain finely dispersed chromatin, which imparts an optically clear or empty appearance, giving rise to the designation ground glass nuclei. Immunohistochemical analysis performed on paraffin sections revealed diffusely and strongly positive for surfactant apoprotein A (SPA), cytokeratin (CK), CK7, CK19, thyroid transcriptor factor-1 (TTF-1), focally and weakly positive for HBME-1, p63, and negative for TG in the pulmonary tumor tissue. Based on the above features, the diagnosis of primary pulmonary papillary carcinoma with lymph node metastasis in the left pulmonary hilum was confirmed.

Discussion

Conclusion