A Case of Rapidly Progressing Thyroid Goiter Associated with IgG4 Infiltration and Autoimmune Thyroid Disease

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: MON 471-496-Thyroid Neoplasia & Case Reports
Clinical
Monday, June 17, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board MON-489
Louis Bondaz*, Antonio Maietta, Louis Guertin, Olguta Gologan, Élise Rodrigue, Marie-José Miron and Rebecca Leboeuf
CHUM, Montreal, QC, Canada
Background: Fibrous Variant of Hashimoto’s Thyroiditis (FVHT) often presents as a rapidly enlarging goiter with obstructive symptoms. Histologically, it is characterized by fibrous infiltration of the thyroid parenchyma without extension outside the thyroid capsule (in contrast with Riedel’s thyroiditis) along with typical changes of Hashimoto’s thyroiditis in the remaining thyroid. It is linked to thyroid autoimmunity in a majority of patients. IgG4-Related Sclerosing Disease is a recently recognized entity presenting with infiltrative involvement of one or more organs, along with elevated serum IgG4 levels. An association between FVHT and IgG4-Related Sclerosing Disease has been suggested, owing to their histopathological similarities. We report here a case of rapidly evolving goiter with classical features of IgG4 disease.

Clinical case: A 58 year-old woman was known for a stable, asymptomatic and euthyroid goiter for many years. She was referred to ENT service after experiencing rapid progression of her goiter along with compressive symptoms over the last 2 years. Her family history was negative for thyroid neoplasia. She had no radiation exposure and did not present any systemic symptoms. A contrast enhanced neck CT revealed a massive goiter which encircled the trachea and esophagus, without evidence of enlarged lymph nodes. She underwent total thyroidectomy. Pathology examination revealed a benign chronic inflammatory lymphoplasmocytic infiltrate, multiple lymphoid follicles, Hürthle cell metaplasia, dense hyaline fibrosis and signs of obliterative phlebitis. There was no evidence of extracapsular involvement. Immunohistochemistry studies showed a diffuse reactive and polyclonal plasmocytosis with marked IgG4-positive cells. It revealed 60-70 IgG4-positive plasma cells per HPF. The IgG4/IgG ratio was elevated to 0.3. Protein electrophoresis showed a polyclonal hypergammaglobulinemia compatible with a diffuse inflammatory process. Her serum IgG levels were increased to 18.4 g/L (N: 5.39-13.7). IgG4 levels were slightly elevated (0.97 g/L; N: 0.07-0.888) as well as IgG2 (6.13 g/L; N:1.48-5.2). Anti-thyroperoxydase and anti-thyroglobulin antibodies were markedly increased (>1000 IU/mL). Although she was clinically euthyroid, no serum TSH was obtained prior to surgery. Contrast enhanced CT showed no signs of salivary gland, pancreas or retroperitoneal involvement. No other organ involvement was clinically or radiologically present.

Conclusion: This case brings further knowledge into the pathogenesis of FVHT. It supports the hypothesis that the entity may be part of the systemic IgG4-Related Sclerosing Disease and that its presence warrants further periodic systemic surveillance.

Nothing to Disclose: LB, AM, LG, OG, R, MJM, RL

*Please take note of The Endocrine Society's News Embargo Policy at http://www.endo-society.org/endo2013/media.cfm