¹⁸F-Flurodeoxyglucose Positron Emission Tomography/Computed Tomography Findings in a Rare Case of Trichoptysis

A 20-year-old female presented with a history of occasional bouts of severe cough with some episodes of mild hemoptysis of 1 year duration. Apart from hemoptysis, she also complained of some “white thread-like substance” coming out with cough during two such episodes. There was no associated chest pain or fever. She had a history of pulmonary tuberculosis 5 years back, which was declared cured after completing 6 months of antitubercular drugs. Recent chest X-ray showed opacity in the left lung upper lobe region. Noncontrast computed tomography (CT) chest was done outside, showing an ill-defined mass in the left lung upper lobe with associated consolidation. Bronchoscopy was normal. CT-guided FNAC from the mass showed only inflammatory cells and no malignant cells. She was refereed for positron emission tomography-CT (PET-CT) for characterization of the mass. Contrast-enhanced ¹⁸F-flurodeoxyglucose (¹⁸F-FDG) PET-CT was performed following usual protocols. In the waiting room, after ¹⁸F-FDG injection, the patient had a severe bout of cough. While there was no hemoptysis, “white thread-like substance” did come out with mucoid sputum [Figure 1a]. Once the patient stabilized, PET-CT was performed. Maximum intensity projection PET image [Figure 1b] showed a patchy area of mild ¹⁸F-FDG uptake in the left upper lobe region (bold arrow), along with physiological ¹⁸F-FDG uptake in the thymus (arrow). Coronal [Figure 1c and d] and transaxial [Figure 1e and f] contrast-enhanced CT and PET-CT images showed a lobular well-defined left anterior mediastinal mass, measuring 50 mm × 37 mm × 37 mm with no focal FDG uptake. The mass has fatty and fluid components along with enhancing solid non-FDG avid component (bold arrows). Adjacent atelectasis was in the left lung upper lobe with minimal ¹⁸F-FDG uptake. The findings were classical of a mature teratoma. No other abnormality was seen in the rest of the body. The “white thread-like substance” was preserved and sent for pathological examination, which confirmed them to be hairs. The patient then underwent surgical removal of the tumor with left upper lobectomy and postoperative histopathology confirmed the diagnosis. She is completely asymptomatic at 2-year follow-up.

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Figure 1 “White thread-like substance” coming out with mucoid sputum, later confirmed to be hairs (a). Maximum intensity projection PET image (b) showed a mild patchy area of 18F-FDG uptake in the left upper lobe region (bold arrow), along with physiological 18F-FDG uptake in the thymus (arrow). Coronal (c and d) and transaxial (e and f) contrast-enhanced CT and PET-CT images showed a lobular well-defined left anterior mediastinal mass, measuring 50 mm × 37 mm × 37 mm with no focal FDG uptake. The mass has fatty and fluid components along with enhancing solid non-FDG avid component (bold arrows). Adjacent atelectasis was in the left lung upper lobe with minimal 18F-FDG uptake. The findings were classical of a mature teratoma. No other abnormality was seen in the rest of the body

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Mature teratoma is one of the most common causes of anterior mediastinal mass in young females.[1] Pulmonary parenchymal or airway involvement of mediastinal teratoma is rare occurrence and variably labeled as pulmonary rupture or pulmonary parenchymal teratoma fistula.[2] Coughing up of hairs or “trichoptysis” is a rare symptom, but pathognomonic of a teratoma having tracheobronchial communication.[34] The incidence of this complication is exceedingly rare and is seen more commonly with cystic lesion (as in the present case) than solid lesion.[3] Imaging plays an important role in diagnosis.[5] ¹⁸F-FDG PET-CT plays a complementary role in making the diagnosis. Identification is important as surgery is curative.[6]