PMC9892196_01
Cervical B-ultrasound. (A) Solid mass in the middle and upper pole of the right lobe of the thyroid gland, 33.4 x 14.5 x 21.2 mm (red circle). (B) The right cervical region VI lymph node showed enlargement, up to 12 x 6 mm (blue circle).
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F1
Neck ultrasonography revealed a 33.4 mm x 14.5 mm x 21.2 mm solid mass in the middle-upper right lobe of the thyroid gland (Figure 1A) and an enlarged right cervical lymph node (12 x 6 mm) in level VI (Figure 1B).
Langerhans cell histiocytosis (LCH) of the thyroid concurrent with PTC: (A) PTC region (blue circle), LCH region (red circle, 1 x). (B) Junctional zone between PCT and LCH (blue circle, 20 x). (C) LCH region (red arrow, 40 x). (D) PCT region (blue arrow, 40 x). (E) Hashimoto's thyroiditis, lymphoid follicle (red arrow), atrophic thyroid follicles (blue arrow) (10 x). (F) Langerin (+) indicated that LCH cells were found in the stroma of PTC (blue circle, 20 x). (G) CD1a cytoplasmic/membrane + (20 x). (H) Langerin cell membrane + (20 x), (I) S-100 nucleus/cytoplasm + (20 x).
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F2
In the low-power HE section, two regions of the thyroid lesions showed LCH and PTC (Figure 2A). PTC (Figure 2B). LCH cells have abundant cytoplasm, are mildly eosinophilic, have epithelioid/histiocytoid appearance, have large and irregular nuclei, slightly atypical nuclei, and diverse morphology, with vacuolated or "coffee bean" appearance, inconspicuous nucleoli, and scattered eosinophilic infiltration in the stroma (Figure 2C). PTC cells were crowded, with ground-glass nuclei, large nuclei, irregular karyotypes, and visible nuclear furrows (Figure 2D). The remaining sections of the thyroid gland were Hashimoto's thyroiditis (Figure 2E), with lymphoid follicle formation and atrophic changes in thyroid follicles. Langerin + LCH cells were present in the papillary stroma of PTC (Figure 2F) and CD1a +, langerin +, and S-100 + LCH cells were determined in the LCH region (Figures 2G-I). LCH areas showed a Ki-67 index of 40%.
Langerhans cell histiocytosis of the lymph nodes: (A) The pink-stained area at the subcapsular sinus was that of LCH (4 x). (B) LCH cells were diffusely distributed with eosinophils (40 x). (C) Nuclear positivity for cyclin D1 (20 x). (D) Variable nuclear positivity for p53 (40 x).
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F3
The LCH metastasis was identified in the subcapsular sinus of the lymph node under low magnification (Figure 3A). At high magnification, LCH cells had more abundant eosinophilic cytoplasm, large and irregular nuclei, slightly atypical nuclei, and diverse morphology, with vacuolated or "coffee bean" -like appearance, and scattered eosinophils in the stroma (Figure 3B). The differential expression of cyclin D1 and p53 helps to exclude reactive hyperplasia Langerhans cells, which was more supportive of LCH (Figures 3C, D).