Late diagnosis of neurofibromatosis type 1 masquerading as thyroid cancer metastasis for six years - The pivotal role of multimodal MRI in a patient with anaplastic thyroid carcinoma

Sep 23, 2026

Uploaded by Mary Man

Neurofibromatosis type 1 (NF1) is an inherited tumor predisposition syndrome linked to multiple benign and malignant neoplasms. A 55-year-old man with thyroid carcinoma diagnosed 6 years earlier was referred for MRI of a slowly progressive right submandibular mass and a left fronto-temporal brain lesion long presumed metastatic. Multimodal MRI showed features not typical of aggressive metastases: absent diffusion restriction and hyperperfusion in the brain lesion, with MR spectroscopy suggesting a low-grade glial tumor. The submandibular lesion was well circumscribed and T2 markedly hyperintense, favoring neurofibroma. Targeted examination then identified café-au-lait macules, axillary freckling, and diffuse cutaneous neurofibromas, supporting NF1 diagnosis by revised criteria, emphasizing multimodal MRI against anchoring bias through clinical correlation.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages5

Reading Time13 min

AccessFree to download

Case Report

Case presentation

Brain MRI findings

Cervical MRI and submandibular lesion

Radiology Ca s e Reports 21 (2026) 4156 – 4160 Available online [at](at www.sciencedirect.com)[ www.sciencedirect.com](at www.sciencedirect.com) journal [homepage:](homepage: www.elsevier.com/locate/radcr)[ www.elsevier.com/locate/radcr](homepage: www.elsevier.com/locate/radcr) | Case Report
Late diagnosis of neurofibromatosis type 1 masquerading as thyroid cancer metastasis for six years: The pivotal role of multimodal MRI in a patient with anaplastic thyroid carcinoma ✩
Anwar Kalali∗, Mahmoud Hsairi, Achraf Saidi, Jalil E. Fakir, Hamza Retal, Najwa E.C. Kettani, Meriem Fikri, Firdaous Touarsa
Neuroradiology Department, Ibn Sina University Hospital, Rabat, Morocco | | | | --- | --- | --- | | a r t i c l e i n f o | | a b s t r a c t | | Article history:
Received 26 April 2026 Revised 26 May 2026 Accepted 1 June 2026 | | Neurofibromatosis type 1 (NF1) is a hereditary tumor predisposition syndrome associated with multiple benign and malignant neoplasms. We report the case of a 55-year-old man with a history of thyroid carcinoma diagnosed 6 years earlier, who was referred for MRI evaluation of a slowly progressive right submandibular mass and a left fronto-temporal brain lesion that had long been considered metastatic disease. Multimodal MRI demonstrated imaging features inconsistent with aggressive metastases. The brain lesion showed no diffusion restriction or hyperperfusion, while MR spectroscopy revealed a prominent myoinositol peak suggestive of a low-grade glial tumor. The submandibular lesion was well circumscribed and markedly hyperintense on T2-weighted imaging, favoring a neurofibroma. These radiological findings prompted targeted physical examination, which revealed multiple café-au-lait macules, axillary freckling, and diffuse cutaneous neurofibromas, leading to the diagnosis of NF1 according to revised international criteria. This case highlights the important role of multimodal MRI in challenging anchoring bias in oncologic patients and emphasizes the value of correlating imaging findings with clinical examination to identify previously unrecognized genetic syndromes.
© 2026 The Author(s) . Published by Elsevier Inc. on behalf of University of Washington.
This is an open access article under the CC BY-NC-ND license
([http://creativecommons.org/licenses/by-nc-nd/4.0/](http://creativecommons.org/licenses/by-nc-nd/4.0/)) | | Keywords:
Neurofibromatosis type 1 Thyroid carcinoma Magnetic resonance imaging Spectroscopy Neurofibroma
Anchoring bias | | | caused by germline mutations in the NF1 tumor suppressor gene. This gene encodes neurofibromin, an important negative regulator of the RAS-MAPK signaling pathway [1] . NF1 is associated with an increased risk of multiple benign and malignant tumors, including tumors of the peripheral nervous ✩ Competing Interests: The authors have declared that no competing interests exist. ∗ Corresponding author. E-mail [address:](address: kalali.anwar@gmail.com)[ kalali.anwar@gmail.com](address: kalali.anwar@gmail.com) (A. Kalali). [https://doi.org/10.1016/j.radcr.2026.06.003](https://doi.org/10.1016/j.radcr.2026.06.003) 1930-0433/© 2026 The Author(s). Published by Elsevier Inc. on behalf of University of Washington. This is an open access article under the CC BY-NC-ND license ([http://creativecommons.org/licenses/by-nc-nd/4.0/](http://creativecommons.org/licenses/by-nc-nd/4.0/)) Fig. 1 – Brain MRI morphological sequences. (A) Axial FLAIR,(B) Postcontrast T1-weighted images show a large left fronto-temporal mass with ring enhancement and no significant perilesional edema and (C) SWI sequence reveals internal signal voids (arrow) consistent with microhemorrhages. system, gliomas, gastrointestinal stromal tumors, pheochromocytomas, and several other neoplasms [2] . The association between NF1 and thyroid carcinoma remains uncommon and poorly documented in the literature. In oncologic imaging, diagnostic anchoring may lead clinicians

FAQs

Why was the patient’s brain and submandibular lesions initially considered metastatic thyroid disease?

The lesions were attributed to metastatic disease because of the patient’s oncologic history, despite the absence of histopathological confirmation.

What multimodal MRI findings argued against aggressive metastases?

The brain lesion showed no diffusion restriction and no significant hyperperfusion, and MR spectroscopy demonstrated a prominent myo-inositol peak suggestive of a low-grade glial tumor.

How was the final diagnosis of NF1 established?

MRI results prompted targeted physical examination, which revealed café-au-lait macules, axillary freckling, and diffuse cutaneous neurofibromas; the case was diagnosed as NF1 using revised international criteria.

Sep 23, 2026

Uploaded by Mary Man