Evaluation of MR imaging findings differentiating parotid basal cell adenomas from other parotid tumors

Yuriko Murayama; Takeshi Kamitani; Koji Sagiyama; Yuzo Yamasaki; Tomoyuki Hida; Yuko Matsuura; Ryuji Yasumatsu; Hidetaka Yamamoto; Hidetake Yabuuchi; Kousei Ishigami

doi:10.1016/j.ejrad.2021.109980

Evaluation of MR imaging findings differentiating parotid basal cell adenomas from other parotid tumors

Eur J Radiol. 2021 Nov:144:109980. doi: 10.1016/j.ejrad.2021.109980. Epub 2021 Sep 27.

Affiliations

¹ Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, 3-1-1, Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
² Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, 3-1-1, Maidashi, Higashi-ku, Fukuoka 812-8582, Japan. Electronic address: kamitani@radiol.med.kyushu-u.ac.jp.
³ Department of Otorhinolaryngology, Graduate School of Medical Sciences, Kyushu University, 3-1-1, Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
⁴ Department of Anatomic Pathology, Graduate School of Medical Sciences, Kyushu University, 3-1-1, Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
⁵ Department of Health Sciences, Graduate School of Medical Sciences, Kyushu University, 3-1-1, Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.

PMID: 34601323
DOI: 10.1016/j.ejrad.2021.109980

Abstract

Purpose: To evaluate the usefulness of magnetic resonance imaging (MRI) to differentiate basal cell adenomas (BCAs) from other parotid tumors.

Method: A total of 136 patients with histologically proven parotid gland tumors (13 BCAs, 66 pleomorphic adenomas [PAs], 30 Warthin tumors [WTs], and 27 parotid cancers [PCs]) who underwent a cervical MRI study between December 2011 and March 2019 were retrospectively enrolled. The MRI findings of the tumors were evaluated by two board-certified radiologists.

Results: All 13 of the BCAs showed smooth margins, while 19 of the 27 PCs showed irregular margins (p < 0.0001). Eleven BCAs had some cystic components, and five were cyst-dominant. The BCAs had significantly more cystic components than the PAs (p = 0.0077). The mean apparent diffusion coefficient (ADC) value of the BCAs was 1.21 ± 0.20 × 10^-3 mm²/sec, which was equivalent to that of the PCs (1.12 ± 0.25 × 10^-3 mm²/sec, p = 0.76), significantly lower than that of the PAs (1.61 ± 0.32 × 10^-3 mm²/sec, p < 0.0001), and significantly higher than that of the WTs (0.81 ± 0.19 × 10^-3 mm²/sec, p = 0.0004). The plateau time-intensity curve (TIC) was the most common type for both BCAs and PCs, seen in 8 of 12 BCAs and 21 of 26 PCs, with no significant difference between these groups (p = 0.34).

Conclusions: BCA should be considered a possibility when a parotid lesion has smooth margins with an entire capsule and includes a cystic component, even if the TIC and diffusion-weighted MR images suggest a malignant pattern.

Keywords: Basal cell adenoma; MRI; Parotid cancer; Parotid gland; Pleomorphic adenoma; Warthin tumor.

MeSH terms

Adenoma*
Diagnosis, Differential
Diffusion Magnetic Resonance Imaging
Humans
Magnetic Resonance Imaging
Parotid Gland / diagnostic imaging
Parotid Neoplasms* / diagnostic imaging
Retrospective Studies