INTRODUCTION: Pulmonary Hyalinizing Granuloma is a rare benign entity, with less than seventy published cases in the English literature, including the two defining review series from Engleman et al. and Yousem and Hochholzer. We present this case of rapidly growing, benign nodules to add to the known literature on the subject.
CASE PRESENTATION: The patient is a 56-year-old male who was referred to the Pulmonary Clinic for abnormal chest radiograph, which was obtained due to concerns regarding prior asbestos exposure. He denied symptoms of dyspnea at rest or with exertion, chest pain or pressure, fevers, chills, cough or night sweats. He has had no weight loss and had a good appetite. He is a former smoker who quit 20 years prior, after a 15 pack-year history. He has a history of osteoarthritis and psoriasis. He also states that he had a liver biopsy in the 1960s which revealed “cirrhosis” and for which he was treated for three years with methotrexate. He does not drink, nor use illicit substances. He was exposed to asbestos in a paper mill job in the late 1960s. On physical exam, he is afebrile with normal vital signs. His HEENT, lymphatic, cardiovascular, abdominal and neurologic exams are normal. His lungs are clear. No clubbing, cyanosis or rashes are seen. Hematologic and chemistry profiles, including liver function tests, reveal no abnormalities. The chest radiograph reveals multiple, solid, dense pulmonary nodules of varying sizes seen in all lobes. These lesions were not present on a radiograph taken two years prior. Computed Tomography scans verify the presence and nature of these nodules. Representative slices from this scan are seen below. Tumor markers, including beta-HCG, AFP, CEA and PSA are normal. The ACE level is normal and a PPD skin test is negative. A colonoscopy and esophagogastroduodenoscopy are both negative as well. The patient was referred for CT-guided biopsy of a lower lobe nodule. The pathology from this biopsy revealed Pulmonary Hyalinizing Granuloma, which was verified by the Mayo Clinic in Rochester, MN.
DISCUSSIONS: Pulmonary Hyalinizing Granuloma is a rare, benign tumor which usually presents in a bilateral manner, and is often initially considered to be suggestive of metastatic disease, autoimmune disorders or pulmonary Histoplasmosis. These lesions are often well-circumscribed, solid and variable in size. Cavitations have been described in at least one circumstance. Both stable and rapidly growing radiographic patterns are found in the literature. Microscopically, these typically perivascular lesions are composed of homogenous, pink, hyaline lamellae which are often surrounded by collections of plasma cells, histiocytes and lymphocytes. The lamellae are often parallel or storiform in formation. Ischemic necrosis, calcified collagen, and positive staining and polarized light assessment for amyloid have been seen as well, but not universally. Autoimmune phenomena, such as positive antinuclear antibodies, rheumatoid factors and Coomb's tests, have also been described, but in no definable pattern amongst these patients. Positive tuberculin skin tests, histoplasmin skin tests, and fungal exposures have also been described regularly, again without pattern. Other fibrosing phenomena, such as fibrosing mediastinitis and retroperitoneal fibrosis have been linked to this disorder in small numbers.
CONCLUSION: Our patient represents another case of Pulmonary Hyalinizing Granuloma, a benign disorder which is to be considered in the differential diagnosis of bilateral, solid and variably-sized nodular lesions. The association with autoimmune and other poorly understood fibrosing disorders leads us to believe that further immunologic investigations may lead to better understanding of prognosis and treatment options.
DISCLOSURE: Richard Kamm, None.