Plasma cell granuloma

Plasma cell granulomas (PCGs) are uncommon, non-neoplastic lesions of unknown etiology and are considered an entity of IgG4-related diseases.

[3] Common sites of plasma cell granulomas are in the oral gingiva, lungs, vagina, larynx, orbit, spinal cord meninges, breast, pelvic soft tissue, bladder, mesentery, retroperitoneum, kidney, lymph nodes, spleen, pancreas, liver, stomach, heart, thyroid, and trachea.

[3] With granulomas that arise in the mouth, PCGs are commonly misclassified considering the malignancy of the disease due to its aggressive behavior and clinical presentation.

[4] It is imperative that such differentiation between plasma cell granuloma and plasmacytomas are completed prior to informing the patient undergoing clinical examination.

[4] While plasma cell granulomas are often found to be benign, plasmacytomas have been associated with a more aggressive and invasive behavior in which they have the ability to transform or evolve into multiple myeloma.

Analyzing the changes that arise in the tissue associated with the mass-forming lesion has been found to be the most accurate and precise method for confirming the diagnosis of plasma cell granulomas.

[3] Common results associated with kappa/lambda in-situ hybridization studies of PCGs are an abundant population of CD138 positive polyclonal plasma cells.

[3] Immunohistochemical staining of plasma cell granulomas is an important diagnostic method to show PCG lesions are also an entity within the IgG4-related diseases.

[3] Even though IgG levels can be measured in serum, histopathological analysis has been concluded to be the most accurate characterization method of PCG lesions.

[3] When surgical removal of the granuloma is not applicable due to size or location, the lesions have been found to respond well to radiation therapy as well as glucocorticoids or steroids.

[3] While recurrence rate for plasma cell granulomas is very low, they have been reported; therefore, it is recommended that patients come back for yearly follow up visits.

This image was originally posted to Flickr by Pulmonary Pathology at https://flickr.com/photos/30950973@N03/5601450952 (archive). It was reviewed on 3 October 2019 by FlickreviewR 2 and was confirmed to be licensed under the terms of the cc-by-sa-2.0.
General image of plasma cell granuloma that was classified in a broader category of inflammatory pseudotumor. Original author of image was: Yale Rosen from USA [ 10 ]
Blech et al. – Biophysical J 2019 116 1637: "Structure of a Therapeutic Full-Length Anti-NPRA IgG4 Antibody: Dissecting Conformational Diversity" were describing that IgG4 has an unusual preferred configuration that is different to the classical Y-shape described for many other antibodies. See there for details. [ 11 ]