Nodular pulmonary amyloidosis with an unusual protein composition diagnosed by fine‐needle aspiration biopsy: A case report

Abstract

Nodular pulmonary amyloidosis is rare, but a number of individual cases have been reported in the literature. Radiologically, pulmonary amyloid nodules often mimic cancer and hence require biopsy to obtain a specimen for definitive diagnosis. We describe a case of isolated nodular pulmonary amyloidosis with an unusual amyloid composition that given the patient's clinical history has not been described in the literature to the best of our knowledge, making this case unique. A 58-year-old woman with a history of mixed connective tissue disease was found to have multiple lung nodules on chest computed tomography (CT) that were radiologically suspicious for cancer. A CT-guided percutaneous fine-needle aspiration (FNA) biopsy of one of the nodules was performed. A diagnosis of amyloid was rendered using special stains and polarized light microscopic examination. Immunohistochemical stains revealed that the amyloid comprised beta-2 microglobulin as well as both kappa and lambda light chains. Further work up showed no evidence of systemic amyloidosis. We were successful in rendering an accurate diagnosis of a pulmonary amyloidoma on material procured by CT-guided FNA thus avoiding more invasive procedures. In addition, immunohistochemical staining revealed an unexpected and highly unusual protein composition of the amyloid.

The lung in amyloidosis

“…It is defined as one or more nodular amyloid deposits involving the lung. It usually represents localised AL (immunoglobulin light chain) or AL/AH (mixed immunoglobulin light chain/heavy chain) amyloidosis [16,17], but rare cases of systemic AL, localised AA, localised ATTRwt and localised Aβ2M/AL (mixed β2-microglobulin/immunoglobulin light chain) amyloidosis have been reported [18][19][20][21][22][23][24]. Of note, localised AL amyloidosis is not unique to the lungs and the tracheobronchial tree.…”

An Organ System–Based Approach to Differential Diagnosis of Amyloid Type in Surgical Pathology

“…ATTRm and ATTRwt are found in fewer than 15% of symptomatic patients, although the lung is second only to the heart with regard to ATTR deposition. AA has an even lower incidence 61,62 and there are single case reports of pulmonary ALECT2 63 and Ab 2 M. 64 Pulmonary amyloid can have 3 distinct histologic patterns. The diffuse alveolarseptal type usually is associated with systemic AL amyloidosis and very infrequently with AA, ATTRwt, and ATTRm amyloidosis.…”

Pancreatic amyloidoma associated with elevated CA19‐9: A case diagnosed by endoscopic ultrasound‐guided fine‐needle aspiration biopsy

“…Amyloidoma, also called amyloid tumor, is a nodular amyloid deposit. It is the least common presentation of amyloidosis and a well‐known mimicker for neoplasm . Amyloidosis is often associated with plasma cell dyscrasias (such as multiple myeloma, Waldenstrom macroglobulinemia, monoclonal gammopathy of undetermined significance (MGUS), and rarely B cell type Non‐Hodgkin lymphoma) and chronic inflammatory diseases (such as rheumatoid arthritis, Sjögren syndrome, and tuberculosis) .…”

“…Amyloidoma has been reported in multiple body sites, including the respiratory tract, the urinary system, breast, eye adnexa, central nervous system, skin, salivary glands, and soft tissue . The pancreas is an extremely rare location.…”