A Rare Cause of Pulmonary Nodules

Abstract

INTRODUCTION: Pulmonary hyalinizing granuloma (PHG) is a rare lung disease characterized by presence of single or multiple lung nodules. The disease is often asymptomatic and diagnosis requires histopathologic confirmation. PHG generally carries a good prognosis. Significant amelioration of respiratory symptoms is often seen with corticosteroids CASE PRESENTATION: A 40-year-old, housewife, with no known comorbids, presented with complaints of cough and shortness of breath for around 10 months. She reported that cough is mostly non-productive, associated with shortness of breath even on mild activity. She also mentioned low-grade fever with fatigue but no weight loss. She had a 10 pack years history of smoking. She denied joint pains, skin rash or ulcers. She had no family history of TB or lung cancer. On physical exam, her respiratory rate was 20 bpm, and SpO2of 99% on room air with no digital clubbing. There were normal vesicular breath sounds on chest auscultation. Chest X-Ray (fig. 1) showed bilateral multiple rounded opacities. CT chest (fig. 2A, 2B) revealed multiple nodules and masses of variable shapes and sizes. Investigations showed ANA positivity with fine speckled pattern but Anti-dsDNA, RA factor and ENA profile were negative. Bronchoscopy and BAL was offered but she refused. She then underwent CTguided biopsy (fig. 3A,3B,3C) that showed cores of fibrocollagenous tissue with dense keloid like collagen arranged in whorls with interspersed histiocytes and lymphocytes. Special stains including congo red, AFB, Periodic acid schiff diastase(PASD) were negative. She was diagnosed as Pulmonary hyalinizing granuloma. Marked clinical response was seen with corticosteroids within 3 weeks of initiation of treatment.DISCUSSION: PHG was first reported in 1964 by Benfield. The occurrence of this disease is linked to an exaggerated immune response to any infectious or autoimmune processes. Lhote et al. published a case series of PHG in 2016 and performed a detailed analysis of 135 cases of PHG published between 1964 and 2015. The results revealed that median age of presentation is usually 44 years with male gender predominance and the most common presenting symptom was cough being 44%. Conditions associated with PHG were wide in number including infections in 14.1%, autoimmune diseases in 12.1%, tumors in 4.4% and various other causes. CT-guided percutaneous biopsy of lesions is required to confirm the diagnosis. Radiographic improvement in the nodules was more frequent in patients treated with corticosteroids than patients without treatment ( 42.1% and 4.4 % respectively).CONCLUSIONS: PHG remains a unique nodular lung disease. It is a great mimicker of pulmonary metastases and tuberculosis. Hence this case signifies the histopathologic confirmation in all such cases where tuberculosis remains an endemic disease and a high probability of metastatic disease should not distract the clinician from rarities