A 62-year-old man with systemic AL amyloidosis was admitted to our hospital because of fever. The patient had noticed bilateral leg edema one year ago, and an annual medical check-up revealed an abundance of protein in the urine. He was referred to a different hospital for further investigation and a renal biopsy, followed by the diagnosis of AL amyloidosis. Amyloidosis was found in the heart, intestines, and tongue, among other organs. The Department of Hematology in our hospital was referred to the patient. In the hematology department, he received autologous peripheral blood stem cell transplantation after receiving combined melphalan and dexamethasone therapy. Following this, he was treated with six courses of combined melphalan and dexamethasone therapy. Laboratory tests showed elevated C-reactive protein levels at 5.29 mg/dL and normal cell count. He presented with mild renal impairment (serum creatinine level of 1.08 mg/dL). Moreover, his immunoglobulin G level decreased to 753 mg/dL. Additionally, we tested him for beta-D-glucan, Aspergillus galactomannan antigen, cytomegalovirus antigen, and anti-glycopeptidolipid-core IgA for Mycobacterium avium and performed interferon-gamma release assay; however, these tests were negative.
Chest radiography showed pleural effusion in the right thoracic cavity and bilateral ground-glass opacity. Chest computed tomography scan revealed right pleural effusion and multiple micronodules with a random distribution in both lung fields (Fig. 3).
Transthoracic echocardiography revealed a low ejection fraction with moderate left ventricular hypertrophy and granular myocardial appearance.
Hence, miliary tuberculosis was suspected. Next, sputum, urine, and blood smear assessments were performed to detect mycobacterium. However, Ziehl-Neelsen staining showed no acid-fast bacillus.
Exudates were discovered during a thoracocentesis, although the culture of pleural effusion samples did not show common bacteria or acid-fast bacteria.
Although there was a risk of TBLC in patients with lung volume loss and a low ejection fraction, we considered that the risk of cancer was significantly higher than that of TBLC. The patient then underwent flexible bronchoscopy to examine the cause of multiple pulmonary micronodules. The bronchus surface was normal on flexible bronchoscopy. We collected lung specimens from the right B2b, B3a, and B4a via both forceps biopsy and cryobiopsy. We used a guide sheath under radiographic guidance and performed TBLB and TBLC through the same guide sheath left behind in the target bronchus. This approach allowed us to take both TBLB and TBLC specimens theoretically from the same place in the lung, minimizing the difference in the sampling error between TBLB and TBLC. The forceps biopsy specimen showed no microbiological findings based on gram staining, Ziehl-Neelsen staining, and Grocott staining. Further, the specimen cultures had negative results.
The pathological findings of the specimen collected via forceps biopsy showed no evidence of amyloidosis. However, those taken via TBLC revealed mild thickening of the alveolar wall and pulmonary arterioles, both of which had amyloid deposition with a positive finding on Congo-red staining (Fig. 4A-D) accompanied by birefringence using polarized light (Fig. 4E).
The lung lesion was associated with systemic amyloidosis. The patient then received continuous chemotherapy for systemic amyloidosis with melphalan and dexamethasone, and his disease behavior has been stabilized for one year to date.
Chest computed tomography scan revealed right pleural effusion and multiple micronodules with a random distribution in both lung fields.