Abstract
The patient presented to the ear, nose and throat clinic with failed conservative treatment of persistent right otitis externa. On examination, the roof of the right ear canal was polypoid and the tympanic membrane could not be visualised. There was a fragile mass noted in the external auditory canal (EAC) which on microsuction started to bleed. CT internal auditory meatus and MRI internal auditory meatus identified soft tissue mass in the EAC. The patient underwent urgent examination under anaesthetic of the ear and biopsies were taken. He had a background of ascending colon cancer; Duke’s C1, pT4, N1 M0, R0 resection and had undergone laparoscopic right hemicolectomy with adjuvant chemotherapy, in the previous year. The biopsy results proved that the mass in the EAC was due to metastatic deposit of colorectal primary tumour. The patient also had a full body CT which revealed other new metastases. The patient is being treated with palliative chemotherapy.
Keywords: surgery; general surgery; gastrointestinal surgery; oncology; ear, nose and throat
Background
Metastatic tumours to external auditory canal (EAC) are very rare. There are only three reported cases of metastatic colorectal adenocarcinoma to the external ear.1–3 Usually cancers of the ear are primary cancers. Some of the common cancers of ear include ceruminous adenoma, adenoid cystic carcinoma, pleomorphic adenoma and ceruminous adenocarcinoma. There are five different pathways of metastatic spread to the temporal bone: isolated metastasis from primary tumour, direct extension from the primary tumour, meningeal carcinomatosis, leptomeningeal extension from an intracranial primary tumour and lymphomatous infiltration.4 Malignancies located in the abdomen can ascend via the thoracic duct into the head and neck. The right lymphatic duct drains from right half of the thoracic cavity, right side of the head and neck and right upper limb.5 The patient described in the case report also had other new metastases.
Metastatic cancer to the ear can be wrongly diagnosed as a benign pathology and not recognised as cancer. Early identification can help with management and treatment.
Case presentation
The patient presented to the ear, nose and throat clinic with failed conservative treatment of persistent right otitis externa. He had several weeks’ history of discomfort and creamy, bloody discharge from the right ear. This was diagnosed as otitis externa and was not improving despite conservative treatment with antibiotics (topical and oral) and pope wick. The patient has not had any previous otologic surgery. Examination revealed a fragile polypoid mass which began to bleed on microsuction (figures 1 and 2).
Figure 1.
Image of the right ear of the patient with the lesion in the external auditory canal.
Figure 2.
Close-up image of the right ear of the patient with the lesion in the external auditory canal.
Medical history
Metallic aortic and mitral valve replacements—on warfarin.
Laparoscopic right hemicolectomy (2016)—Duke’s C1, pT4, N1 M0, R0.
Chemotherapy (2016).
Social history
Lives at home with wife, independent.
Investigations
Imaging
Imaging was done to investigate the mass further.
CT internal auditory meatus
Soft tissue opacification in the right EAC.
MRI internal auditory meatus
Evidence of right EAC enhancing soft tissue mass measuring approximately 3×1.8 cm in size (figure 3).
Figure 3.
MRI internal auditory meatus demonstrating the soft tissue mass in the external auditory canal—coronal section.
Examination under anaesthetic of right ear (surgery) and biopsy
Colorectal metastatic adenocarcinoma.
CT neck+thorax+abdomen+pelvis
Recurrent mass at the anastomotic site in the right side of the retroperitoneum along with multiple mesenteric and peritoneal metastatic deposits and small volume upper abdominal lymph nodes. The mediastinal lymph nodes are stable, with the increase in the left pleural effusion and stable mild right pleural effusion.
Histopathology
Appearances are those of an adenocarcinoma, partly having a signet ring morphology. Some cells show cytoplasm vacuolation and very occasional small, rounded luminal structures are suggestive of glandular differentiation.
Immunohistochemistry
Tumour cells react with CDX2 and villin, with <5% reacting with CK20. A mucicarmine stain demonstrates mucinous material in cell cytoplasm within small luminal spaces.
Differential diagnosis
Exostoses.
EAC medial canal fibrosis.
Malignant otitis externa.
Cholesteatoma.
Benign soft tissue tumours (eg, aural polyp, lipoma, haemangioma).
Malignant tumours (eg, osteochondroma, osteosarcoma, Ewing’s sarcoma, squamous cell carcinoma, basal cell carcinoma and melanoma).
Treatment
Palliative chemotherapy was decided prior to finding the EAC lesion as there was CT proven anastomotic recurrence of colonic adenocarcinoma with multiple mesenteric and peritoneal metastases.
Outcome and follow-up
Outcome: Palliation; the patient was screened for the Keynote 177 trial.
Otologic outcome: Inoperable adenocarcinoma.
Follow-up: Palliative chemotherapy, outpatient oncology review.
Discussion
Most cancers of the ear are primary cancers of the EAC. Metastatic cancers to the EAC are rare.
There are three reported cases of metastatic colorectal adenocarcinoma to the external ear. Carson et al1 report a case of a 63-year-old man with stage II adenocarcinoma of the colon who presented with right-sided hearing loss. A mass in the EAC was identified as metastatic adenocarcinoma. This was removed and hearing improved. Carr and Anderson2 describe a case of a patient with rectal adenocarcinoma who presented with a metastatic mass in the EAC despite CT chest, abdomen and pelvis being clear for metastasis. Sadek et al3 also report a metastatic carcinoma of the external ear from rectal carcinoma.
Other common cancers that metastasise to the external ear canal are from breast, renal and bronchogenic cancers.5–8
Learning points.
Metastases to the external ear canal are rare but can also mask themselves as benign pathologies such as otitis externa.
If external auditory canal (EAC) lesions do not respond to antibiotic therapy, consider biopsy.
For a patient presenting with mass in the EAC, metastatic cancer should be considered as a differential.
Acknowledgments
The authors thank the patient and the family.
Footnotes
Contributors: AJ: contributed to the design of the case report, acquisition, analysis and interpretation of data; drafted and submitted the work. SK: provided care for the patient and identified the patient for case report; acquired data and interpretation of data; provided feedback on the written work and made relevant changes. SB: provided care for the patient and identified the patient for case report.
Funding: The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests: None declared.
Patient consent: Obtained.
Provenance and peer review: Not commissioned; externally peer reviewed.
References
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