Two lymphoma histotypes and papillary thyroid carcinoma coexisting on Hashimoto ground: a case report and review of the literature

Abstract

Background: Papillary carcinoma is the most frequent type of thyroid carcinoma, while primary thyroid lymphoma is uncommon disease. The coexistence of these entities has already been described, and the common risk factor is considered Hashimoto thyroiditis. The two most frequent histotypes of primary thyroid lymphoma are diffuse large B-cell and mucosa-associated lymphoid tissue lymphoma, but the coexistence of both with papillary carcinoma is rarely reported.

Methods: We present a case of a previously healthy 57-years old male with rapidly growing lump on the right side of the neck. Ultrasonography revealed nodules in both thyroid lobes. Fine needle aspiration cytology and pertechnetate scintigraphy were performed. Due to the Bethesda T-5 in the "cold" nodule of the right lobe, surgery with histopathological and immunohistochemistry analysis was indicated.

Results: Histopathological and immunohistochemistry methods confirmed concomitant malignancies in the thyroid gland: diffuse large B-cell lymphoma and papillary carcinoma in the right, and mucosa-associated lymphoid tissue lymphoma in the left lobe with Hashimoto thyroiditis in the remaining tissue. Patient underwent therapy procedures and was without signs of local recurrence or metastatic spread on subsequent follow-up.

Conclusions: Sudden appearance of the neck mass in patients with Hashimoto thyroiditis should raise suspicion on primary thyroid lymphoma and be promptly taken in the diagnostic workup, including fine needle aspiration cytology. Pathology with immunohistochemistry is crucial for further clinical decision making. Since the standardized protocol in management of these complex patients is missing, personal approach and close collaboration between cytologist, pathologist, surgeon, haematologist and nuclear medicine specialist is essential.

Keywords: Diffuse large B-cell lymphoma; Hashimoto thyroiditis; Mucosa-associated lymphoid tissue lymphoma; Papillary thyroid carcinoma; Primary thyroid lymphoma.

Fig. 1

a Thyroid ultrasound. Right thyroid lobe with hypoechoic, perinodally vascularized nodule measuring 30 × 25 × 36 mm. b Thyroid ultrasound. Left thyroid lobe with hypervascularized, irregular hypoechoic area measuring 20 × 12 × 16 mm

Fig. 2

Thyroid ^99mTc pertechnetate scintigraphy showing cold area in the right thyroid lobe indicated by arrow

Fig. 3

a DLBCL. Diffuse proliferation of medium sized to large lymphoid cells with vesicular nuclei with 2–4 nuclear, membrane-bound nucleoli (centroblasts—red arrows) or immunoblasts (large cells with single, central nucleolus) (Giemsa, magnification 40x). b MALT lymphoma. Predominate medium sized lymphocytes with round nuclei resembling those of centrocytes, in between are scattered large transformed cells (Giemsa, magnification 40x)

Fig. 4

a-c Immunohistochemical staining of DLBCL area. The majority of the cells are immunohistochemically negative for CD10 (A, magnification 20x), while Bcl-6 staining is positive (B, magnification 20x) with very high Ki-67 proliferation index (C, magnification 10x)

Fig. 5

a Tumour tissue is composed mainly of follicles lined by layer of cells showing nuclear characteristics of the papillary thyroid carcinoma (HE, magnification 100x). b Strong and diffuse cytoplasmic immunohistochemical staining with anti CK19 confirms papillary thyroid carcinoma (CK19, magnification 100x)

Fig. 6

a-c Immunohistochemical staining of extranodal marginal zone lymphoma (MALT-oma). CD10 (A) and Bcl-6 (B) staining is negative with low Ki-67 proliferation index (C); in the image B and C recognizable germinal centers which are Bcl-6 positive and have high Ki-67 proliferative index (A-C, magnification 20x) can be seen