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Case Reports
. 2024 Sep 9;16(9):e68987.
doi: 10.7759/cureus.68987. eCollection 2024 Sep.

Intrathyroidal Thymoma: A Diagnostic Challenge

Adhithya N Balaji  1 , Balaji Balasubramanian  2 , Juman A Hazeem  3
Affiliations
Case Reports

Intrathyroidal Thymoma: A Diagnostic Challenge

Adhithya N Balaji et al. Cureus. .

Abstract

Intrathyroidal thymoma is a rare tumor that can be challenging to diagnose due to its unusual location and resemblance to more common thyroid conditions. We present the case of a 58-year-old woman with an incidentally discovered thyroid nodule during evaluation for an upper respiratory infection. Ultrasonography revealed an exophytic nodule in the left thyroid lobe, categorized as TR 3. Fine-needle aspiration cytology suggested a neoplastic process, leading to a left hemithyroidectomy. Histopathology confirmed a diagnosis of intrathyroidal thymoma, Type B2, with extensive necrosis, and immunohistochemistry validated the findings. This case underscores the diagnostic challenges of intrathyroidal thymoma, emphasizing its consideration in the differential diagnosis of atypical thyroid nodules. Despite the difficulties in preoperative identification, surgical resection and subsequent histopathological examination remain essential for a definitive diagnosis. The patient is currently under surveillance, and there is no evidence of residual thymic tissue or abnormalities in the remaining thyroid tissue.

Keywords: aberrant thymic tissue; ectopic thymoma; fnac; immunohistochemistry; intrathyroidal thymoma; thymoma; thyroid.

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Conflict of interest statement

Human subjects: Consent was obtained or waived by all participants in this study. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work.

Figures

Figure 1
Figure 1. Ultrasound (US) image of the thyroid gland showing an exophytic nodule measuring 4.6 x 3.4 cm, having a solid and cystic component with a spongiform appearance arising from the lower pole of the left lobe of the thyroid gland.
Figure 2
Figure 2. FNAC of the left thyroid nodule reveals areas of lesional cell necrosis (black arrowhead) adhering to small hyperchromatic nuclei (yellow arrow) without clear cytoplasm.
Magnification: 400× FNAC: fine-needle aspiration cytology
Figure 3
Figure 3. The surgical specimen from the left hemithyroidectomy, measuring 7 × 2.5 × 2 cm and weighing 16 g.
Figure 4
Figure 4. Histopathology of the nodule stained with H&E showing no follicular cells.
(A) 200× magnification; (B) 400× magnification H&E: hematoxylin and eosin
Figure 5
Figure 5. Immunohistochemistry panel of the nodule with the following stains: (A) CD3, (B) CD5, (C) CD45, (D) CD99, (E) CK 5/6, (F) p63, (G) CK (AE1/AE3), (H) CD20, and (I) vimentin.
Immunohistochemistry of the nodule showed positivity with the following stains: (A) CD3 (polyclonal), (B) CD5 (4C7), (D) CD99 (12E7), (E) CK 5/6 (D5/16 B4), (F) p63 (Dak-p63), (G) CK (AE1/AE3), and (H) CD20 (L26), while it showed patchy positivity with (I) vimentin (V9)
See this image and copyright information in PMC

References

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