Lymphocytic/Hashimotos Thyroiditis, TBSRTC category II.
Histopathology:
- adequate cellular smear for evaluation
- few follicles with hurthle/oncocytic cell changes (abundant granular dense eosinophilic cytoplasm and well defined cell border)
- cells shows marked nuclear enlargement and hyperchromasia, some with smudgy nuclear atypia.
- Evaluate the location of nucleus, it is not eccentric in above case.
- Evaluate the chromatin pattern, it not neuroendocrine type in above case
- Few cells show nucleoli
- thin colloid and blood in background
- sparse lymphocytes in background
- Diagnostic features of papillary thyroid carcinoma and medullary thyroid carcinoma are not appreciated.
Points of Pathoclinics:
- Moderate to marked atypia in follicular cells can be seen in Hashimotos thyroiditis, Hurthle cell neoplasm, follicular neoplasm, Long standing goiter, medullary thyroid carcinoma and anaplastic carcinoma of thyroid
- Presence of lymphocytic cells rule out Hurthle cell neoplasm. If the lesion is of pure population of hurthle cells, than the TBSRTC category IV is appropriate.
- Elevated level of anti-thyroid peroxidase and anti-thyroglobulin antibodies support the cytology diagnosis.
- Medullary thyroid carcinoma is close differentials, especially oncocytic variant. Presence of high cellularity, loose aggregates as well as single plasmacytoid or spindle cells, frequent bi-nucleated cells, salt pepper chromatin, eccentric location of nucleus and amyloid favors medullary thyroid carcinoma.
- Carefully look for nuclear inclusions and grooves to rule out oncocytic variant of papillary thyroid carcinoma.
- Number of lymphocytes has no co-relation with clinical, biochemical, radionuclide and ultrasonographic parameters.
- IgG4 positive plasma cells in Hashimotos thyroiditis are significantly associated with presence of lobulation, oncocytic metaplasia and certain type of fibrosis, fibrosis spread outside the gland, lymphocytes/plasma cells epithelial penetration, the predominance of micro follicles and follicular atrophy. Hashimotos thyroiditis with IgG4-positive plasma cells is histopathologically distinct entity. Epithelial degeneration is more common in IgG4 positive plasma cell infiltrating Hashimotos thyroiditis.
Reference:
Bhatia A, Rajwanshi A, Dash RJ, Mittal BR, Saxena AK. Lymphocytic thyroiditis–is cytological grading significant? A correlation of grades with clinical, biochemical, ultrasonographic and radionuclide parameters. Cytojournal. 2007 Apr 30;4:10. doi: 10.1186/1742-6413-4-10. PMID: 17470291; PMCID: PMC1877811.CopyDownload .nbibFormat
Lintusaari J, Vesaniemi E, Kalfert D, Ilvesaro J, Ludvíková M, Kholová I. IgG4-positive plasma cells in Hashimoto thyroiditis: IgG4-related disease or inflammation-related IgG4-positivity? APMIS. 2020 Sep;128(9):531-538. doi: 10.1111/apm.13067. Epub 2020 Jul 6. PMID: 32578252.
