Thyroid gland
Miscellaneous non-neoplastic disorders
Plasma cell granuloma

Author: Andrey Bychkov, M.D., Ph.D. (see Authors page)

Revised: 25 January 2017, last major update April 2015

Copyright: (c) 2015-2017, PathologyOutlines.com, Inc.

PubMed Search: Plasma cell granuloma thyroid
Cite this page: Plasma cell granuloma. PathologyOutlines.com website. http://pathologyoutlines.com/topic/thyroidpcgranuloma.html. Accessed October 21st, 2017.
Definition / general
  • Marked polyclonal plasma cell infiltration with nodular or diffuse thyroid involvement
Terminology
  • Also known as plasma cell granuloma type of inflammatory pseudotumor; but sclerosing type of inflammatory pseudotumor of thyroid is mainly composed of spindle cells (Eur Arch Otorhinolaryngol 2009;266:763, Endocr Pathol 2009;20:186)
  • Note: at other sites, the term inflammatory myofibroblastic tumor (or inflammatory pseudotumor) is usually used because myofibroblasts are common, and it is understood that some variants will have numerous plasma cells; however, in the thyroid gland, these cases are still called plasma cell granuloma because there are usually marked plasma cell infiltrates and myofibroblasts are usually limited
Epidemiology
  • ~ 20 cases reported, mainly middle age and elderly women (range, 18 - 89 years, M/F = 1:4)
Pathophysiology
Clinical features
  • Neck mass with compression signs
  • Mainly indolent clinical behavior
  • Often accompanied by hypothyroidism or Hashimoto thyroiditis
Diagnosis
  • Histology after biopsy or surgery
Radiology description
  • Nonspecific; solitary benign nodule or diffuse involvement on ultrasound, cold nodule on scintigraphy
Case reports
Treatment
  • Lobectomy / partial excision for nodular lesion, total thyroidectomy for diffuse form
  • Conservative steroid and immunosuppressive therapy (J Clin Endocrinol Metab 2004;89:1534)
  • No recurrences / metastases after excision
Gross description
Gross images

Images hosted on other servers:

Multinodular

Cut surface

Microscopic (histologic) description
  • Abundant benign plasma cells forming sheets inside cellular fibroblastic stroma with residual thyroid tissue
  • Variable lymphocytes and histiocytes, and occasional polymorphonuclear leukocytes or eosinophils
  • Russel bodies (aggregates of immunuoglobulin) within plasma cells; Russel bodies may form grape-like clusters
  • Mott cells (plasma cells with spherical inclusions packed in their cytoplasm, Endocr Pract 2008;14:611)
  • Hürthle cell changes of follicular epithelium in thyroid with diffuse involvement
  • Rare sclerosing subtype is hypocellular with focal uniform spindle cells / myofibroblasts arranged in fascicles; large histiocytes, lymphocytes, plasma cells and scattered eosinophils are in background
Microscopic (histologic) images

Images hosted on other servers:

Plasma cells, lymphocytes and fibrous tissue

Clumps of plasma cells

Plasma cells around follicular epithelium

CD79a

Kappa and lambda light chains

Various stains

Positive stains
Negative stains
  • ALK1 for spindle cells (no positive cases reported so far)
Molecular / cytogenetics description
  • No monoclonality by PCR