INTRODUCTION:PET scans are frequently used to manage patients with cancer and assess nature of mass lesions in the lungs. Although intense FDG uptake is most frequently associated with cancer, some inflammatory lesions, particularly those with granuloma formation can also have high uptake. We report an unusual case of pleural based masses with high FDG uptake in a patient with LAM and history of osteosarcoma.
CASE PRESENTATION:A 29 year old woman with a remote history of osteosarcoma was evaluated for progressive pulmonary disease due to LAM and need for lung transplantation. Symptoms were dyspnea on minimal exertion and slight cough productive of small amounts of white sputum. She had no chest pain, weight loss, fever or sweats. She continued to work part-time as a bookkeeper but was fatigued. She had no exposure to TB and no significant travel history. Past medical history was significant for osteosarcoma at 7 years of age treated with chemotherapy and right above-knee-amputation. She developed renal insufficiency believed secondary to mitomycin therapy. At age 24 she developed episodic pneumothoraces and ultimately underwent bilateral talc sclerosis for occurrence of simultaneous bilateral pneumothoraces. LAM was diagnosed on lung biopsy at that time and she was also noted to have an angiolipoma. She was treated briefly with leuprolide. She had no further pneumothoraces but cystic changes slowly progressed with worsening respiratory function. Renal insufficiency worsened as well. Social history included that she smoked few cigarettes daily for the last 10 years and used alcohol occasionally. Family history was non-contributory. Physical exam was unremarkable except for a slight wheeze on auscultation of the chest and right Above-Knee-Amputation. Labs were notable for creatinine of 5.0 mg/dl. Pulmonary Function Test showed combined obstructive and restrictive ventilatory defects with FEV1 of 1.07 L, 29% predicted and DLCO of 37% predicted. Chest CT scan showed progression of cystic changes in the lung consistent with LAM and pleural based masses with high attenuation that had progressed from mild thickening seen on CT scan three years previously. A left upper lobe posterior pleural-based mass measured 2.5x2.0 cm and a peripheral right lower lobe 0.9 × 0.6 cm. PET scan showed three large foci of increased FDG uptake in both lungs in areas of CT involvement but more extensive than suggested by the CT scan. SUV ranged from 3.9 to 8.2 and was consistent with metastatic disease. Left thoracotomy with biopsy of the plural-based nodules showed no cancer but exuberant foreign body giant cell reaction with focal necrosis, hyaline fibrosis and polarizable foreign material. The pathology was consistent with talcomas.
DISCUSSIONS:Pneumothorax and talc pleurodesis are common in LAM. Solid pleural masses are reported in up to 14% of patients after pleurodesis. These masses, similar to our case may increase over time and be confused with cancer. Characteristic CT features for talcomas are high attenuation masses with pleural thickening. FDG uptake can be intense and appears to persist over years. This is likely due to the granulomatous reaction make up the talcomas.
CONCLUSION:After talc sclerosis, talcomas with high FDG uptake can occur and be confused with metastatic cancer.
DISCLOSURE:Aly Hemdan Abdalla, No Financial Disclosure Information; No Product/Research Disclosure Information