CT and MR of recurrent primary cutaneous adenoid cystic carcinoma with multiple metastases

Abstract

Primary cutaneous adenoid cystic carcinoma is a rare slow-growing neoplasm, with limited literature reporting the involvement of the scalp. It has a tendency to recur locally; however, lymph node, distant pulmonary and bony metastases are exceptionally rare. We highlight the case of a 65-year-old female with primary cutaneous adenoid cystic carcinoma with distant pulmonary and bony metastases and the importance of imaging in diagnosing distant metastasis and perineural spread.

Figure 1.

CT imaging of the neck shows an ill-defined homogeneously enhancing lesion in the left preauricular region of the scalp extending into the left masticator space causing erosion of the squamous part of the temporal bone with intracranial extension (arrow).

Figure 2.

Bone window revealed an expansile, osteolytic lesion of the clivus involving dorsum sellae and the posterior clinoid process (arrow).

Figure 3.

CT axial image bone window shows no bony sclerosis or foraminal widening on the left (arrows).

Figure 4.

MR shows a hyperintense lesion in the pre- and postauricular region (arrow).

Figure 5.

Apparent diffusion coefficient map shows a value of 0.132 × 10⁻³ mm² s⁻¹ favouring a malignant lesion.

Figure 6.

T₁ weighted contrast-enhanced axial MR image with fat saturation shows enhancement of the left foramen ovale and spinosum (arrow), indicating perineural spread via the mandibular branch of the left trigeminal nerve.

Figure 7.

T₁ weighted contrast-enhanced axial MR image with fat saturation shows the lesion involving the region of the left stylomastoid foramen (arrow), indicating perineural spread via the facial nerve.

Figure 8.

T₂ weighted fluid-attenuated inversion-recovery coronal image shows hyperintensity in the left Meckel's cave (arrow), indicating perineural spread via the left trigeminal nerve.