A Case Report Demonstrating How the Clinical Presentation of the Diffuse Sclerosing Variant of Papillary Thyroid Carcinoma Can Mimic Benign Riedel’s Thyroiditis

Abstract

A 44-year-old female presented with a two-month history of a neck mass, sore throat, hoarseness, and intermittent dysphagia. Examination revealed a “woody” hard swelling arising from the right lobe of the thyroid. Clinically this was felt to be classical Riedel's thyroiditis (RT). Thyroid ultrasound showed a diffusely enlarged, low echogenicity thyroid with a multinodular goitre. An abnormal nodule extending across the isthmus was noted. Following a nondiagnostic fine needle aspiration, an open core biopsy was performed. This showed dense sclerotic fibrosis punctuated by nodular mononuclear inflammatory cells, which obscured follicular epithelial cells consistent with a fibrosing thyroiditis (Riedel's thyroiditis). A biopsy of pretracheal lymph nodes showed a sclerotic process throughout the lymph nodes and nests of epithelium bands with squamous differentiation obscured by a fibrous process. These findings raised the differential diagnosis of diffuse sclerosing variant of papillary thyroid carcinoma (DSV-PTC) with metastasis to lymph nodes. A total thyroidectomy and pretracheal lymph node dissection were performed. The final histological diagnosis was DSV-PTC. When managing a patient with presumed RT it is important to consider malignancy in the differential. DSV-PTC is one of the more aggressive forms of thyroid cancer but with early diagnosis and appropriate treatment patients may have excellent outcomes.

An unusual presentation of diffuse sclerosing variant of papillary thyroid carcinoma

“…Definitive diagnosis is made on the basis of the presence of several pathological features including a diffuse firm enlargement of the thyroid gland with scattered islands of papillary carcinoma, extensive lymphatic permeation, and lymphocytic infiltration, extensive squamous metaplasia, a large number of psammoma bodies, and a prominent fibrosis. These histological features are essential in distinguishing PTC from benign pathologies such as Riedel's and Hashimoto's thyroiditis [6,7]. The preoperative diagnosis of DSV remains difficult, and it can be diagnosed preoperatively based on a combination of typical imaging findings and careful cytological examination [8,9].…”

Establishment of an Ultrasound Malignancy Risk Stratification Model for Thyroid Nodules Larger Than 4 cm

“…Pathology analysis of surgical samples indicated Riedel’s thyroiditis, a rare inflammatory process involving thyroid and surrounding cervical tissues that is associated with systemic fibrosis ( 26 ). The nodules associated with this condition show nonspecific ultrasound features and so are often misdiagnosed ( 27 , 28 ).…”

Riedel's Thyroiditis. A Clinical Review.

“…Тиреоидит Риделя чаще встречается у женщин и манифестирует в возрасте старше 50 лет. [3,4] Предложено несколько теорий возникновения тиреоидита Риделя. Существуют мнения, что тиреоидит Риделя может быть исходом подострого тиреоидита, тиреоидита Хашимото или лекарственно индуцированным заболеванием.…”

“…Современные данные предлагают в качестве диференциальной диагностики тиреоидита Риделя с другими формами тиреоидитов проведение ИГХ -исследования, по данным которого в послеоперационном материале выявляется большое количество IgG4+ плазматических клеток, как очередное подтверждение IgG4+ ассоциированного характера заболевания. [3,8]. Консервативное лечение включает в себя прием глюкокортикоидов для устранения воспалительной реакции (преднизолон 15-100мг/сутки), или же тамоксифена (10-20мг/сутки), механизм действия последнего до конца неизвестен, но считается, что эффект связан с ингибированием пролиферации фибробластов.…”