Pulmonary hyalinizing granuloma (PHG) is a rare fibro-sclerosing inflammatory lung tumor of unknown etiology. Patient presentation varies from asymptomatic to vague chest-related symptoms. Most of the lesions are incidental radiological findings. The nature of PHG presents diagnostic difficulties for clinicians.
A 75 year-old man with past medical history of smoking and treated tuberculosis presented with failure to thrive. He complained of generalized weakness, cough associated with yellow sputum as well as forty-seven pounds weight loss over the last year. The physical examination revealed a cachectic male in no acute distress with normal vital signs. The chest examination showed decreased bilateral air entry at the upper lung fields. A chest roentgenogram revealed bilateral opacification of both upper lung zones (fig. 1). Computer tomogram was performed (fig. 1) and showed no changes compared with the previous CT obtained nine months earlier. Fiberoptic bronchoscopy revealed no endobronchial lesions and the transbronchial biopsy as well as the bronchioalveolar lavage were negative for malignancy or active tuberculosis. CT-guided biopsy was performed and three core specimens from upper lobes were obtained (fig 2). The biopsies showed a serpentine array of dense hyalinized collagen bundles accompanied by few lymphocytes and plasma cells. The histological picture of lamellar fibrosis with chronic inflammation favored PHG.
PHG is a rare pathology that presents most commonly as slowly enlarging nodules in lung parenchyma. PHG was first described in 1977 to define an unusual pulmonary tumor characterized by numerous regularly arranged lamellae of hyalinized collagen (1). This condition is uncommon and no more than 70 cases have been reported so far (1,2,3). PHG affects adults in the age range of 24 to 77 years without sex predilection (3). The etiology and pathogenesis remain unclear. However, it has been suggested that the nodules represent an exaggerated host reaction to a number of agents, such as Histoplasma capsulatum, Tuberculosis or Aspergillus (1,2,3). Many patients are asymptomatic, however, cough, dyspnea, chest pain, and hemoptysis may occur. PHG usually appears as bilateral nodular lesions 2 to 4 cm in diameter, simulating metastatic tumors. Large lesions with or without cavitation have been reported as well (1,2,6). The nodules are well demarcated and often “shell out” easily from surrounding lung parenchyma. Histologically, they consist of numerous inter-connecting lamellae of homogeneous, hyalinized collagen. Plasma cells, occasional lymphocytes and multinucleated giant cells are present in small numbers between the lamellae and adjacent to blood vessels. There is no effective treatment for this condition. Surgery was the most effective treatment for most patients with single PHG’s (3). Two recent case reports described successful treatment with corticosteroids (4,5).
PHG is a rare explanation for pulmonary nodules. Our case stands out due to larger size and single bilateral dense apical lesions. Only one similar case was reported by Russell (6).
D. Lvovsky, None.