A Case of Black Thyroid Associated with Hyalinizing Trabecular Tumor

Abstract

Abstract. Black thyroid is an uncommon phenomenon of black pigmentation of thyroid parenchyma induced by chronic minocycline therapy. Thyroid tumors associated with black pigmented thyroid are rare. We describe here a 42-year-old woman with a black thyroid associated with hyalinizing trabecular tumor (HTT). The patient presented with a palpable left-sided thyroid nodule. She had taken minocycline for aphthous stomatitis and an oral ulcer for 9 years. The findings of fine needle aspiration biopsy and BRAF mutation analysis suggested a papillary carcinoma. The patient underwent a neartotal thyroidectomy with central compartment node dissection. The surgical specimen showed a diffuse black thyroid and a 2-cm non-pigmented, well-circumscribed nodule in the left thyroid. Histopathologically, numerous black pigmented follicular epithelial cells and colloid were seen throughout the thyroid parenchyma, and the nodule was composed of elongated, polygonal cells in trabecular arrangement and dense hyaline stromas. The tumor cells showed a strong positive cytoplasmic reaction to Ki 67. All of these findings suggested a HTT, or a hyalinizing trabecular variant of papillary carcinoma, arising in a black thyroid. To our knowledge, this is the first case of black thyroid associated with HTT. BLACK thyroid, or black pigmentation of the thyroid, was first described in humans in 1976 [1]; to date only 64 cases have been reported in the English language literature [3][4][5][6][7][8][9][10][11][12][13][14]. The black discoloration usually develops after taking minocycline, a tetracycline derivative, for several years. Thyroid tumors associated with black thyroid are extremely rare, but may include adenomatous hyperplasias, adenomas, and papillary and follicular cancers [3][4][5][6][7][8][9][10][11][12][13][14]. To our knowledge, however, hyalinizing trabecular tumor (HTT) arising in black thyroid has not previously been reported. CaseA 47-year-old woman presented with a 5-year history of a solitary thyroid nodule. She had a history of taking minocycline intermittently over 9 years for aphthous stomatitis and oral ulcer of Behcet's disease. On examination, a mild black discoloration of the teeth and gums was identified (Fig. 1), in addition to the palpable nodule. Neck ultrasound disclosed a wellcircumscribed hypoechoic nodule, measuring 2.0-cm diameter, in the left thyroid. Fine needle aspiration biopsy (FNAB) revealed a few clusters of follicular cells with nuclear clearing, grooves, and pseudoinclusions; and a BRAF mutation (V600E) was detected by the dual-priming oligonucleotide (DPO) primer method. These findings were suspicious for papillary thyroid carcinoma. A near-total thyroidectomy with central compartment node dissection was performed, and intraoperative frozen section of the nodule suggested the

Cytologic Features and BRAF Mutation of Hyalinizing Trabecular Adenoma of the Thyroid - A Case Report with Review of the Literature -

“…However, case 2 displayed a BRAF gene mutation, although histopathological and immunohistochemical findings were entirely compatible with HTA. A similar case demonstrating discrepant results was previously documented by Kang et al 12 They reported a case of black thyroid associated with HTA. In their case, the thyroid tumor showed typical histopathological features of HTA and characteristic membranous MIB-1 staining, whereas a BRAF mutation, which is specific to PTCs, was also present.…”

“…In the frozen sections subjected to touch imprint or scrape smear cytology, two of the four cases were initially reported as PTC and one as MTC but the remaining one was "suspicious of a hyalinizing trabecular tumor, adenoma vs carcinoma." 12 These results may be rare for this tumor and are not typical cytological features of HTA. One patient also had an occult papillary carcinoma in the opposite lobe of the thyroid, measuring 0.3 cm.…”

“…The pathogenetic mechanism of minocyclin associated with HTA has not been described. 12 As for the HTA itself, they were all solitary masses ranging from 1.6 to 4 cm. According to those studies, all masses were well circumscribed or encapsulated and homogeneously solid and devoid of hemorrhage or necrosis, as in the present case.…”

“…In Korea, two cases of HTA have been reported using cytological findings, whereas two other cases have been reported without cytological findings. [12][13][14][15] The clinical and cytohistological findings of all reported Korean cases are summarized in Table 2. All patients, including the present case, were females ranging from 40 to 55 years old.…”

The Thyroid Pathologist Meets Therapeutic Pharmacology

“…Similar findings have been observed in thyroidectomy specimens (Fig. 3 ), and in both benign and malignant thyroid nodules, pigmentation has been reported in all combinations: unpigmented nodule and pigmented thyroid parenchyma, pigmented nodule and pigmented thyroid parenchyma, and, rarely, pigmented nodule and unpigmented parenchyma [ 20 – 27 ].

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