Melanoma of the External Auditory Canal: A Review of Seven Cases at a Tertiary Care Referral Center

Neoplasms of the Ear Canal

Primary EAC neoplasms include benign and malignant lesions of bony, glandular or cutaneous origin. Small, benign slow growing bony neoplasms are often asymptomatic, diagnosed incidentally and might not require intervention. Both malignant and benign neoplasms of cutaneous and glandular origin can present with symptoms of chronic otitis externa, leading to delays in diagnosis. Prompt biopsy of soft tissue lesions associated with non-resolving otitis externa are warranted. Local and regional imaging is helpful to understand disease extent and origin, but even early-stage malignant neoplasms require aggressive surgical treatment.

Gastric metastasis from nodular malignant melanoma of the auricle with multigene aberrations: A rare case report and literature review

Primary malignant melanoma (MM) of the external ear accounts for a low proportion of cases of cutaneous MM, and its incidence in non-white women is very low. The stomach is a rare metastatic site for MM. Gastric metastasis of MM of the external ear is extremely rare, and the associated gene alterations and mechanisms are poorly understood. The present report describes the case of a 58-year-old Asian woman who had a mass on the left auricle for 5 years and was diagnosed with nodular MM with the BRAF V600E mutation after surgical resection. Postoperative metastases to the stomach and descending duodenum appeared 1 year after resection. After 11 months of BRAF-targeted therapy and immunotherapy, the patient developed drug resistance and died from systemic metastases to the brain, lungs, liver, left adrenal gland and peritoneum. Genetic testing revealed additional aberrations in MYB, p16, MYC and PTEN. The clinical characteristics of MM of the external ear and gastric metastatic MM were also summarized through a retrospective literature review. Immunohistochemical staining is critical in the diagnosis of gastric metastasis from MM of the external ear. This disease often requires a multidisciplinary treatment approach, including surgery, targeted therapy and immunotherapy. The present study provides some genetic information about this rare disease and discusses appropriate treatment strategies. The findings of the present study suggests that the surgical margin size, tumor histological type and number of genetic aberrations may be closely associated with metastasis potential, therapeutic efficacy and patient outcome.

Malignant Melanoma of the External Auditory Canal on 68 Ga-FAPI PET/CT

ABSTRACT

External ear melanomas are relatively rare and usually occur in the regions of helix and ear lobes. Rarer still are primary melanomas of the external auditory canal. We report findings of melanoma of the external auditory canal on 68 Ga-FAPI PET/CT in a 56-year-old man who presented with sharp pain in the external auditory canal for 7 months.

Temporal Bone Resection for Squamous Cell Carcinoma of the Lateral Skull Base: Systematic Review and Meta-analysis

OBJECTIVE

Temporal bone squamous cell carcinoma (TBSCC) is rare and often confers a poor prognosis. The aim of this study was to synthesize survival and recurrence outcomes data reported in the literature for patients who underwent temporal bone resection (TBR) for curative management of TBSCC. We considered TBSCC listed as originating from multiple subsites, including the external ear, parotid, and external auditory canal (EAC), or nonspecifically from the temporal bone.

DATA SOURCES

PubMed, Cochrane Library, Embase, and manual search of bibliographies.

REVIEW METHOD

A systematic literature review conducted in December 2020 according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

RESULTS

Survival data were collected from 51 retrospective studies, resulting in a pooled cohort of 501 patients with TBSCC. Compared to patients undergoing lateral TBR (LTBR), patients undergoing subtotal (SBTR) or total (TTBR) TBR exhibited significantly higher rates of stage IV disease (P < .001), positive surgical margins (P < .001), facial nerve involvement (P < .001), and recurrent disease (P < .001). A meta-analysis of 15 studies revealed a statistically significant 97% increase in mortality in patients who underwent STBR or TTBR. On multivariate analysis, recurrent disease was independently associated with worse overall survival (P < .001). On univariate analysis, facial nerve involvement was also associated with decreased overall survival (P < .001).

CONCLUSION

Recurrent disease was associated with risk of death in patients undergoing TBR. Larger prospective multi-institutional studies are needed to ascertain prognostic factors for a wider array of postoperative outcomes, including histology-specific survival and recurrence outcomes.

High expression of lncRNA HSD11B1-AS1 indicates favorable prognosis and is associated with immune infiltration in cutaneous melanoma

Cutaneous melanoma is an aggressive malignant cancer associated with poor prognosis. Identification of reliable biomarkers for predicting prognosis of melanoma contributes to improved clinical outcome and disease management. Long non-coding RNAs (lncRNAs) serve a crucial regulatory role of oncogenesis and tumor suppression in melanoma. Using data from The Cancer Genome Atlas database, novel lncRNA 11β-hydroxysteroid dehydrogenase type 1-antisense RNA 1 (HSD11B1-AS1) was identified, which was significantly downregulated in malignant melanoma and its downregulation was significantly associated with poor clinicopathological characteristics, including advanced T and pathological stage, Clark level, Breslow depth and ulceration and worse prognosis. Multivariate analysis showed that HSD11B1-AS1, as well as N stage and Breslow depth, were independent prognostic factors in cutaneous melanoma, and nomograms suggested a good predictive value of 1-, 3- and 5-year overall survival, progression-free interval and disease-specific survival. In vitro experiments verified the decreased HSD11B1-AS1 expression in melanoma cell lines compared with human epidermal melanocytes. Moreover, cell experiments in vitro, including Cell Counting Kit-8, colony formation, wound healing and Transwell assay, suggested that overexpression of HSD11B1-AS1 significantly inhibited melanoma cell proliferation, migration and invasion. Functional enrichment showed significantly enriched pathways in IFN-γ and -α response, TNF-α signaling via NF-κB and IL-2/STAT-5 and IL-6/JAK/STAT-3 signaling. In addition, immune infiltration analysis demonstrated that HSD11B1-AS1 may function by accelerating immune response regulation and the immune cell infiltration of various immunocytes, especially T, T helper 1, activated dendritic and B cells. The present study revealed HSD11B1-AS1 as a potential therapeutic target and promising biomarker for diagnosis and prognosis of cutaneous melanoma.