CRA82 A DIAGNOSTIC CHALLENGE: SMEAR NEGATIVE PULMONARY TUBERCULOSIS UNMASKED AS IGG4-RELATED LUNG DISEASE

Ken Nee Ong¹, Kong Yong Chong², Benedict Dharmaraj A/L Retna Pandian², Narasimman A/L Sathiamurthy², Hui-Xin Tan¹

¹ Respiratory Unit, Internal Medicine Department, Hospital Sungai Buloh, Selangor, Malaysia
² Thoracic Surgery Unit, Hospital Kuala Lumpur, Malaysia

IgG4-related disease (IgG4-RD) is a multisystemic fibroinflammatory condition characterized by elevated serum IgG4 levels and lymphoplasmacytic infiltrates in various organs. Pulmonary involvement may manifest in the form of pulmonary nodules and masses, often mimicking lung neoplasm, or pulmonary tuberculosis, which is endemic in our region.

Hereby we present a lady with a persistent right upper lobe lung mass after completing 9 months of anti-tuberculous therapy for smear negative pulmonary tuberculosis and tuberculous myelitis. Her lung biopsy during intensive phase of treatment was negative for malignancy, and Mycobacterium tuberculosis (MTB) culture was negative. She remained asymptomatic, with no chest nor systemic complaints.

A follow-up CT scan showed a slightly enlarging, more spiculated lung mass. Bronchial washings for MTB Gene Xpert and MTB culture were both negative, and her second lung biopsy HPE was consistent with an inflammatory myofibrohistiocytic lesion. Her PET CT scan demonstrated a focal intensive FDG uptake at the right upper lobe (SUVmax 18.9). In view of her suspicious lung mass, she was referred to thoracic surgeon and underwent a uniportal right VATS upper lobectomy and lymphadenectomy. Histopathological examination of the resected tissue was suggestive of IgG4 related lung disease. She was subsequently managed by a rheumatologist and commenced on corticosteroids and Azathioprine.

This case highlights the importance of considering IgG4 related lung disease as an uncommon cause of persistent lung lesion in asymptomatic young patients. When non-surgical biopsies are inconclusive, early referral for thoracic surgery is crucial in establishing a definitive diagnosis.