Thyroid crisis caused by metastatic thyroid cancer: an autopsy case report

Abstract

Background: Thyroid crisis is a life-threatening condition in thyrotoxic patients. Although differentiated thyroid cancer is one of the causes of hyperthyroidism, reports on thyroid crisis caused by thyroid cancer are quite limited. Here, we describe a case of thyroid crisis caused by metastatic thyroid cancer.

Case presentation: A 91-year-old woman was admitted to our hospital because of loss of appetite. Two years prior to this hospitalization, she presented with subclinical thyrotoxicosis and was diagnosed with histologically unidentified thyroid cancer with multiple metastases, and she refused aggressive medical interventions. On admission, she exhibited extreme thyrotoxicosis, and the presence of fever, severe tachycardia, impaired consciousness, and heart failure revealed the presence of thyroid crisis. All thyroid autoantibodies were negative. Multidisciplinary conservative treatment was initiated; however, she died on the fifth day after admission. Autopsy revealed the presence of primary anaplastic thyroid carcinoma and multiple metastatic foci arising from follicular thyroid carcinoma. Both primary and metastatic follicular thyroid carcinoma likely induced thyrotoxicosis, which could have been exacerbated by anaplastic thyroid carcinoma.

Conclusions: Even though the trigger of thyroid crisis in this patient is not clear, the aggravated progression of her clinical course suggests that careful monitoring of thyroid hormones and appropriate intervention are essential for patients with thyroid cancer.

Keywords: Anaplastic thyroid carcinoma; Follicular thyroid carcinoma; Metastasis; Thyroid crisis.

Fig. 1

Clinical course. When the patient was diagnosed with a thyroid tumour, her TSH was under the detection limit, and her thyroid hormone levels were normal; she had subclinical thyrotoxicosis. Her thyroid hormones worsened gradually until 2 weeks before admission; however, thyrotoxicosis rapidly deteriorated in the last 2 weeks. She also had a high Tg level at the first visit, which peaked 2 months before admission and then decreased

Fig. 2

Computed tomography scan. A: The thyroid was markedly swollen with calcification. Tracheal deviation was identified. B: The hilar and mediastinal lymph nodes were swollen. C: Multiple nodules were identified in both lungs. D: A pathological left hip fracture was identified

Fig. 3

Thyroid ultrasonography. A Two years before hospitalization. A large tumour was revealed in the right lobe with calcification and slight blood flow. B At the time of hospitalization. Diffuse enlargement of the right lobe with increased blood flow was revealed

Fig. 4

Gross image of the thyroid. A The thyroid weighed 110 g and was 7.6 × 6.4 × 3.0 cm in size. The thyroid was slightly hard. B The cut surface of thyroid showed a white solid mass with central haemorrhagic necrosis

Fig. 5

Microscopic image of the thyroid. A Nodules with thyroid follicles of various sizes invading the surrounding tissues were mainly observed (hematoxylin and eosin, low magnification). B Atypical spindle tumour cells proliferating solidly without follicles were also observed (hematoxylin and eosin, low magnification). C Enlargement of the image shown in B (hematoxylin and eosin, high magnification). After immunostaining, the spindle tumour cells were positive for cytokeratin AE1/AE3 (D), CAM5.2 (E) and PAX8 (F) (high magnification)

Fig. 6

Pathological findings of left lung. A There were well-defined white lesions in left lung. B Follicles of various sizes were observed and were considered to be metastases of FTC. No anaplastic cancer tissue was found in the metastatic lesions, which all showed findings of FTC (hematoxylin and eosin, low magnification)