SESSION TITLE: Disorders of the Pleura Student/Resident Case Report Posters
SESSION TYPE: Student/Resident Case Report Poster
PRESENTED ON: Tuesday, October 27, 2015 at 01:30 PM - 02:30 PM
INTRODUCTION: Distant metastases of thyroid cancer to the lungs is reported at 3% to 15% (1). We present a rare case of thyroid carcinoma metastatic to lung with extensive pleural involvement.
CASE PRESENTATION: A 69 year old non-smoker male with history of low grade prostate adenocarcinoma 7 years prior presented with progressively worsening shortness of breath on exertion for the last 8 month. He had occasional cough and left sided chest discomfort but denied hemoptysis, dysphagia, neck pain, hoarseness, loss of weight and anorexia. Physical examination showed palpable right anterior and posterior cervical lymphadenopathy and reduced breath sounds on auscultation of the left thorax. A CT chest 2 years prior for surveillance of prostate cancer showed subtle thickening of the pleura at the left base without parenchymal involvement. A new CT chest showed extensive left pleural thickening and nodularity encasing the lung, a large pleural based mass in left lower lobe (LLL) and superior mediastinal lymphadenopathy. A core biopsy of LLL mass was negative for malignancy but a core biopsy of left pleura was diagnostic for metastatic papillary carcinoma of thyroid with follicular variant. The immune profile (positive TTF1, CK7 and thyroglobulin; negative Napsin A, PSA) supported the diagnosis and excluded lung adenocarcinoma, mesothelioma and metastatic prostatic adenocarcinoma. An ultrasound of neck showed a 1.2 cm irregularly calcified nodule in the right lobe of the thyroid along with 2 distinct areas of lymph node enlargement. A thyroglobulin level resulted >4000 ng/ mL with normal TSH. A total thyroidectomy and modified right neck dissection was carried out and revealed pT3, pN1a, pM1 disease. Pathology demonstrated well differentiated papillary thyroid carcinoma, partially encapsulated with lymph-vascular and capsular invasion but minimal extra-thyroidal extension. A PET imaging showed significant FDG uptake in the left pleura and basal mass. Treatment with radioactive iodine (I-131) was instituted.
DISCUSSION: Papillary thyroid cancer is the most common thyroid malignancy. Lung metastasis of follicular variant-papillary thyroid carcinoma is extremely rare. These carcinomas are slow growing and can take months to years to manifest clinically. Pleural metastasis of thyroid cancer is associated with a very poor prognosis; the median overall survival following the appearance of a pleural metastasis is less than a year.
CONCLUSIONS: In this case, a subtle pleural thickening seen on the imaging 2 years prior evolved into aggressive metastasis resulting in remarkable pleural involvement, lung entrapment and respiratory insufficiency. The importance of a wide differential of pleural diseases is emphasized from this case.
Reference #1: Iain J. Nixon et al. The Impact of Distant Metastases at Presentation on Prognosis in Patients with Differentiated Carcinoma of the Thyroid Gland. THYROID. Volume 22, Number 9, 2012.
DISCLOSURE: The following authors have nothing to disclose: Muhammad Iqbal, Christopher McHenry, Edward Sivak
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