Lung - nontumor
Other nonneoplastic disease
Nodular amyloid (amyloidoma)


Topic Completed: 1 October 2011

Revised: 16 January 2019

Copyright: (c) 2003-2019, PathologyOutlines.com, Inc.

PubMed search: "nodular amyloid" OR "amyloidoma" pulmonary

See Also: Amyloidosis

Elliot Weisenberg, M.D.
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Cite this page: Weisenberg E. Nodular amyloid (amyloidoma). PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/lungnontumoramyloidnodular.html. Accessed September 24th, 2019.
Definition / general
  • Rare, presents as asymptomatic nodule
  • Usually in asymptomatic elderly with nodule on chest Xray, but no evidence of systemic disease
  • Good prognosis; typically doesn't progress to lymphoproliferative disorders
  • Nodular involvement may be associated with systemic involvement
Case reports
Gross images

Contributed by Dr. Sajna V.M. Kutty, MVR Cancer Centre and Research Institute, Kozhikode, Kerala, India

Rib tumor

Microscopic (histologic) description
  • Well circumscribed amyloid, often with lymphocytes (T cells) and plasma cells
  • Granulomatous reaction to amyloid common, often calcification and ossification
Microscopic (histologic) images

Contributed by Dr. Sajna V.M. Kutty, MVR Cancer Centre and Research Institute, Kozhikode, Kerala, India

Amyloid deposits

Apple green birefringence



Case of the Week #197

Lung nodules - H&E

Congo red - polarizing microscopy

Cytology images

Case of the Week #197

Fine needle aspiration of lung nodule

Positive stains
  • Congo red staining: glassy, salmon pink amorphous material with apple green birefringence under polarized microscopy
  • Clonal restriction of plasma cells (kappa or lambda staining, not both)
Electron microscopy description
  • Amyloid fibrils
Differential diagnosis
  • Primary pulmonary lymphomas with amyloid production: < 1% of pulmonary lymphomas have amyloid deposits, usually age 70+ years with marginal zone or SLL / CLL subtypes, often with lymphatic tracking and reactive lymphoid follicles; the presence of evenly distributed lymphocytes in the nodule and invasion of the pleura is specific for lymphoma
  • Hyalinizing granuloma: history of exposure to Histoplasma or TB, collagen is Congo red negative
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