AB024. The role of PET scan in differential diagnosis of extrapulmonary involvement in sarcoidosis

Background: Presentation of a case of sarcoidosis with extrapulmonary involvement.

Methods: A 37-year-old woman presented with cough, fever and neurological symptoms (flashing lights, headache, transient paralysis of the right half of the face, gait instability, numbness in legs and swallowing disorders) with duration of four months.

Results: On physical examination, the patient exhibited bilateral, painful on palpation cervical lymph nodes, while findings from respiratory, neurological and ophthalmological assessment were normal. Laboratory tests revealed no abnormalities, besides high levels of serum ACE (225 IU/L). Chest radiography showed a reticulonodular pattern, while HRCT of the thorax depicted mediastinal lymphadenopathy, numerous small nodules with perilymphatic, peribronchovascular and subpleural distribution and interlobar septa nodular thickening. Lung function tests, ECG and ultrasound examination of the heart and of the upper abdomen were normal. The patient underwent bronchoscopy for BAL examination, which revealed lymphocytosis (32%) and a CD4+/CD8+ ratio of 15.5, which was pathognomonic for sarcoidosis, while histopathology of the lesion taken by bronchus biopsy did not reveal granulomas. Due to the high degree of suspicion for neurologic involvement, an EMG of upper and lower limbs was performed, with no pathological findings, while a subsequent brain MRI showed lesions that put the differential diagnosis of demyelinating disease. To exclude extrapulmonary manifestations, the patient underwent PET-CT, which showed typical involvement of the mediastinal and cervical lymph nodes and multiple spleen lesions and excluded CNS involvement. The diagnosis of sarcoidosis was set by the combination of clinical, laboratory and imaging findings. Patient was subsequently administered treatment with low doses of corticosteroids for the management of constitutional symptoms of the disease.

Conclusions: Sarcoidosis is a granulomatous disease with findings from the lungs in 90% of the cases. Extrapulmonary manifestations are common and may involve every organ. PET-CT can be exceedingly helpful for the selection of an appropriate site for biopsy, the estimation of the inflammatory activity and extent of the disease and the assessment of patients with persistent, atypical symptoms, in whom extrapulmonary involvement is suspected.

Keywords: Sarcoidosis; PET scan; extrapulmonary involvement