Carcinoma of the ear: a case report of a possible association with chlorinated disinfectants

Does Hypochlorous Acid Cause Ototoxicity? An Experimental Study

AIM

Hypochlorous acid (HOCl) is a weak acid that ionizes in water. It is an effective antiseptic exhibiting low toxicity on living tissues. We aimed to investigate the ototoxic effects of HOCl on an animal model by using electrophysiological and histological methods.

MATERIALS AND METHODS

The study comprised 32 Sprague-Dawley rats, which were separated into four groups: control group (A), saline solution group (B), 70% isopropyl alcohol + 2% chlorhexidine group (C), and HOCl group (D). After recording the auditory brainstem response (ABR) for basal hearing thresholds (8, 16, 24, and 32 kHz), 0.03 ml of the aforementioned materials was injected intratympanically three times every 2 days in groups B, C, and D. ABR measurements were repeated on the 7th and 21st days. All animals were sacrificed, and temporal bones were prepared for examinations of cochlear histology and vascular endothelial growth factor immunohistochemistry.

RESULTS

Basal hearing levels were normal across all frequencies and groups, with no statistical differentiation. On the 7th and 21st days after the ABR test, all other groups demonstrated a significant deterioration in hearing levels compared with group A. When the results from 7th and 21st days were compared within group D, a partial recovery was observed. In histopathology, groups C and D demonstrated moderate and severe cochlear degeneration, along with decreased immunoreactivity in the organ of Corti, stria vascularis, and spiral ligament.

CONCLUSION

This is the first study to evaluate the safety of using HOCl in otology. Although HOCI is less ototoxic than the disinfectant used, it may have a toxic effect on cochlea.Level of Evidence: Animal Research.

Invasion Patterns of External Auditory Canal Squamous Cell Carcinoma: A Histopathology Study

OBJECTIVES/HYPOTHESIS

To describe the histopathology of the invasion patterns of advanced-stage external auditory canal (EAC) squamous cell carcinoma (SCC). Study Design Retrospective cohort study.

METHODS

Retrospective analysis of medical records of patients diagnosed with EAC SCC available at the Massachusetts Eye and Ear temporal bone (TB) collection. TBs underwent processing for histologic examination. Hematoxylin and eosin-stained slides were examined. Histologic findings were compared to premortem clinical data.

RESULTS

Nine TBs were identified. Male:female ratio was 6:3. The average age of diagnosis and duration of survival was 64 (46-80 years) and 2.3 years (1-50 months), respectively. All presented with T4 disease, most commonly due to petrous apex (PA) invasion and facial nerve (FN) weakness. The mastoid air cells system served as a tumor conduit to the tegmen mastoideum and overlying dura in four patients, posterior fossa dura in one patient, vertical segment of FN in four patients, and middle ear (ME) and lateral semicircular canal in five patients. The tumor did not penetrate the tympanic membrane, oval window membrane (fenestra vestibule), or round window (RW) membrane. Supra- and infralabyrinthine pneumatization patterns allowed direct routes to the PA. Translabyrinthine PA invasion was seen in two patients. The most common locus of otic capsule invasion was the cochlea. One patient had FN paralysis due to compression rather than invasion.

CONCLUSIONS

SCC does not tend to extend from the ME to the inner ear through the RW and vestibule-stapedial ligament. Tumors tend to spread along the preexisting TB air-tract routes. Well-aerated TB, may facilitate extension to the PA.

LEVEL OF EVIDENCE

4 Laryngoscope, 131:E590-E597, 2021.

Management of Temporal Bone Malignancy in Ireland

Objectives  Lateral temporal bone malignancy remains a challenging rare disease. We report 17 years of multidisciplinary care of these tumors with univariate and multivariate analyses of key prognostic indicators for consideration in contemporary oncological management. Design  This is a retrospective cohort study. Setting  This is set at a tertiary referral center. Participants  All patients presenting with histopathologically newly diagnosed cases of temporal bone malignancy between 2000 and 2017 were included. Main Outcome Measures  The main outcome measures are disease-specific and recurrence-free survival rates. Results  In this study, 48 cases of temporal bone malignancy were diagnosed. Median age at diagnosis was 69 years (range: 5-88). Fourteen patients were female. Squamous cell carcinoma was the predominant malignancy in 34 cases (71%). Surgical treatment was undertaken in 37 patients. Mean length of follow-up was 32 months (range: 0.7-117). Overall 5-year disease-specific survival was 52.4%, while overall 5-year recurrence-free survival was 53.5%. On univariate analysis, significantly worse survival was seen in females ( p  = 0.008), those with distant metastatic disease ( p  = 0.041), and in middle ear involvement ( p  = 0.012) with no difference for involvement of the external auditory canal ( p  = 0.98) or mastoid ( p  = 0.78). Only middle ear involvement remained significant on multivariate analysis. Conclusion  A wide variety of malignant pathology may present in the temporal bone. Recurrence-free survival is equivalent to international data; however, this figure is low. This emphasizes the need to treat these tumors appropriately with radical resection, where possible, at first presentation. Therefore, multidisciplinary surgical input is recommended. Middle ear involvement was a negative prognosticator for disease-specific and recurrence-free survivals.

Malignant tumors of the temporal bone - our experience

Introduction

Malignant tumors of the temporal bone are rare, with an estimated incidence of about 0.8–1.0 per 1,000,000 inhabitants per year. The vast majority of these tumors are squamous cell carcinomas and their treatment is eminently surgical.

Objective

This study is an attempt at systematizing the forms of clinical presentation, the therapeutic possibilities, and oncological outcomes of patients with malignant tumors of the temporal bone in a tertiary hospital in Portugal.

Methods

The authors present a retrospective study of temporal bone tumors treated and followed during otorhinolaryngology consultations between 2004 and 2014. A review of the literature is also included.

Results

Of the 18 patients included in the study, 16 had a primary tumor of the temporal bone, in most cases with squamous cell carcinoma histology. Of these, 13 patients were treated with curative intent that always included the surgical approach. Disease persistence was observed in one patient and local recurrence in five patients, on average 36.8 months after the initial treatment.

Conclusions

The anatomical complexity of the temporal bone and the close associations with vital structures make it difficult to perform tumor resection with margins of safety and thus, tumor relapses are almost always local. A high level of suspicion is crucial for early diagnosis, and stringent and prolonged follow-up after treatment is essential for diagnosis and timely treatment of recurrances.

Squamous cell carcinoma of the temporal bone

Squamous cell carcinoma of the temporal bone is a rare, highly malignant, aggressive disease in an extremely difficult anatomic site with a very poor prognosis. The development of an evidence base for the efficacy of its treatment has been hampered by its rarity. This article reviews current opinion based on the recent literature.

Temporal bone carcinoma

Squamous cell carcinoma is the most common malignancy of the external auditory canal, middle ear, and mastoid. Surgical resection is the cornerstone of treatment, with T1 lesions of the external auditory canal treated by lateral temporal bone resection and more advanced lesions treated by subtotal or total temporal bone resection. This article summarizes clinical manifestations, differential diagnosis, management, and differences in treatment philosophy.