Dx: Metastatic follicular thyroid carcinoma
A biopsy of one of the lung nodules was performed and showed strong positive staining for thyroglobulin and thyroid transcription factor-1, establishing a diagnosis of metastatic follicular thyroid carcinoma. Further imaging revealed additional metastases to the brain, liver, adrenal glands, and spine.
Follicular thyroid carcinoma is the second most common histologic type of thyroid cancer, comprising 10% to 15% of thyroid cancer cases.1 Distant metastases are not uncommon in this histologic type; about 11% of patients have distant metastases at presentation.2 Compared with papillary thyroid cancer, which spreads via the lymphatics, the follicular type can metastasize via vascular invasion, thus leading to its “aggressiveness” and frequent occurrence of metastasis outside the neck (most commonly to the lung).1 For this reason, an early diagnosis is important.3 In this case, the patient revealed that she hadn’t sought medical care at the onset of her symptoms due to financial limitations and limited access to medical providers; this likely contributed to the patient’s diagnosis at a late stage of disease.
Infectious and septic diseases are part of the differential Dx
The differential diagnosis for diffuse pulmonary nodules includes various infections, silicosis, coal worker’s pneumoconiosis, septic pulmonary emboli, and pulmonary sarcoidosis. All of these diagnoses can cause constitutional, as well as pulmonary, symptoms.
Infections, such as pulmonary tuberculosis, pulmonary coccidioidomycosis, or other cavitating infections, can be ruled out with specific testing for the organism of concern and/or culture.
Silicosis and coal worker’s pneumoconiosis generally cause lesions in the upper lobes and require a significant occupational exposure to silica or coal, respectively.
Continue to: Septic pulmonary emboli