Surgical management of brain metastasis as a part of systematic metastases from adenoid cystic carcinoma of the external auditory canal: illustrative case.

Shunichiro Kuramitsu,Yasuhiro Nakajima,Ayako Motomura,Mamoru Matsuo,Akinori Kageyama,Iori Kojima,Masasuke Ohno,Nobuhisa Fukaya,Ryuta Saito,Kazuya Motomura,Takashi Tsujiuchi

doi:10.3171/case21673

Abstract

BACKGROUNDAdenoid cystic carcinoma (ACC) of the external auditory canal (EAC) is a rare tumor that accounts for approximately 5% of all EAC tumors. ACC is generally known as a slow-growing tumor, but patients often experience recurrence or distant metastasis in the long clinical course. While the major pattern of recurrence is pulmonary metastasis, brain metastasis of ACC of the EAC is rare.OBSERVATIONSThe authors describe the case of a 72-year-old male who was diagnosed with ACC of the EAC. Approximately 7 years later, brain magnetic resonance imaging revealed an intra-axial homogenously enhancing mass lesion that had no direct connection with the skull base in the left frontal lobe. The patient underwent tumor resection and histopathological examination revealed a mixture of cribriform and tubular patterns. The image and pathological characteristics of the tumor were similar to those of primary ACC or ACC from other sites of origin.LESSONSWhile patients with ACC of the EAC often experience recurrence or distant metastasis in the long clinical course, they survive for a relatively long period of time, even though an optimal treatment has not been established. The authors therefore recommend surgical resection for brain metastasis of ACC of the EAC to improve neurological symptoms.

Highlights

Adenoid cystic carcinoma (ACC) of the external auditory canal (EAC) is a rare tumor that accounts for approximately 5% of all EAC tumors
Brain magnetic resonance imaging (MRI) revealed an intra-axial homogeneously enhancing mass lesion in the left frontal lobe (31 Â 34 mm in size), which had no direct connection with the skull base (Fig. 2A–D)
Observations ACC typically arises from the salivary glands, and surgical resection is the radical treatment of choice, when feasible, followed by radiotherapy.[2,3]

Summary

BACKGROUND

Adenoid cystic carcinoma (ACC) of the external auditory canal (EAC) is a rare tumor that accounts for approximately 5% of all EAC tumors. 7 years later, brain magnetic resonance imaging revealed an intra-axial homogenously enhancing mass lesion that had no direct connection with the skull base in the left frontal lobe. A 72-year-old right-handed male was initially diagnosed with ACC of the left EAC (TNM staging; T1 N0 M0), following partial resection of the tumor at a nearby hospital (Fig. 1A–C). Brain magnetic resonance imaging (MRI) revealed an intra-axial homogeneously enhancing mass lesion in the left frontal lobe (31 Â 34 mm in size), which had no direct connection with the skull base (Fig. 2A–D). P53 (Fig. 4E) and Ki-67 (Fig. 4F) expression were detected in the tumor cell nuclei Based on these pathological analyses, the patient was diagnosed with metastatic ACC tumor. The patient’s family opted for palliative care only and he was transferred to hospice

Discussion

Findings

72 Male Frontal lobe