Blastomyces Induced Otomastoiditis With Local Soft Tissue Invasion: A Case Report

Abstract

The aim of this report is to document a very rare case of Blastomycosis dermatitidis mastoiditis with extension into the retromastoid soft tissue and surrounding muscle. Blastomycosis dermatitidis is a dimorphic fungus of endemic areas which classically infiltrates the lungs; however, dissemination presenting as otomastoiditis is exceedingly rare. The patient was an immunocompetent 27-year-old male with no significant preexisting health conditions. He had significant work exposure to dust and soil and was referred to our department for evaluation of otalgia with headaches, hearing loss, and intermittent facial paralysis. Initially, the extent of the infection was unknown. Based on extensive disease on magnetic resonance imaging, the patient was scheduled for urgent tympanoplasty and mastoidectomy. Postoperative treatment with itraconazole resolved any further manifestations and halted further soft tissue invasion. It is important to consider uncommon fungal infections in the workup of persistent otalgia, especially when presenting with facial paralysis and a history of environmental exposure to soil and dust. This type of infection should be considered regardless of immunodeficiency status. Early detection may prevent hearing loss and local invasion into surrounding structures.

Introduction

Blastomycosis dermatitidis is a fungal disease that traditionally infects the pulmonary system with cutaneous manifestations. ¹ Other systemic involvement has been reported, such as bone, prostate, central nervous system, and rarely the head and neck. ¹ Currently, there are very few published cases of B dermatitidis causing otomastoiditis or mastoiditis. ^2,3 In this discussion, we present a case report of B dermatitidis infection of the mastoid with extension into the retromastoid soft tissue and surrounding muscle, its clinical presentation including novel and detailed imaging, proposed treatment, follow-up, and overall medical relevance.

Case Report

A 27-year-old male with no significant medical history other than a history of smoking presented to urgent care in March 2020 with chief complaints of 1-month history of headache, nasal congestion, and left otalgia. The patient lives in an endemic region and is exposed to dust and soil in his work environment doing farm drainage work. On initial presentation, the physical examination revealed a left middle ear effusion without erythema. He was diagnosed with “eustachian tube dysfunction” and prescribed prednisone 20 mg twice daily for 5 days. Two weeks later, he presented with persistent otalgia, sinus pain, and hearing loss. On physical examination, he was found to have hearing loss, mastoid tenderness, and a stenotic left external auditory canal. He was diagnosed with acute otitis externa and possible scalp cellulitis. The patient was prescribed ofloxacin ototopical drops and trimethoprim-sulfamethoxazole orally.

Four weeks later, the patient returned with persistent otalgia, headaches, and a new complaint of a subcutaneous nodule on his right lower abdominal quadrant that was considered a lipoma. He was switched to neomycin-polymyxin-hydrocortisone otic suspension. Having no improvement, he was seen by otolaryngology 2 weeks later (May 2020) and complained of continued hearing loss and otalgia, swelling of the left posterior superior postauricular area, occasional tinnitus, and new onset of intermittent facial hypesthesia and weakness (House-Brackmann grade II). He denied dizziness and otorrhea. A noncontrast computed tomography of the temporal bones (Figure 1) was ordered followed by a magnetic resonance imaging of the internal auditory canals with and without gadolinium (Figure 2) that suggested severe mastoiditis with meningeal enhancement. An audiogram revealed severe left mixed hearing loss.

Figure 1.

Computed tomography (CT) scan without contrast of temporal bone, showing complete opacification of left mastoid air cells and left middle ear cavity, with regions of cortical erosion and thinning. Soft tissue abnormalities adjacent to the mastoid were noted, suggesting extension into the proximal sternocleidomastoid muscle.

Figure 2.

Magnetic resonance imaging (MRI) with and without contrast showing complete opacification of left middle ear cavity and mastoid with extension into the left petrous apex. Congruent with the computed tomography (CT) scan, this MRI shows extension through the wall of the mastoid suggesting involvement of the adjacent soft tissue. Abnormal dural thickening and enhancement along the floor of the left middle cranial fossa and along the left aspect of the posterior fossa warns of possible extension into the intracranial space.

After evaluation by otolaryngology, an urgent tympanoplasty, mastoidectomy, and T-tube placement was performed. Intraoperatively, fibrous granulation tissue was seen throughout the mastoid and middle ear. A biopsy and cultures were taken intraoperatively, and B dermatitidis growth resulted 2 weeks later. Prior to availability of the culture results, the patient reported continued otalgia. After results were obtained, infectious disease was consulted, serum antibodies and urine antigens were positive for Blastomycosis, and the patient was prescribed itraconazole 200 mg every 8 hours for 3 days followed by a 5-month course of itraconazole, 200 mg every 12 hours.

On follow-up visits, the patient reported improvement in hearing but not to his original baseline. He had complete restoration of facial movement and complete resolution of otalgia and headaches. Additionally, the suspected lipoma resolved, suggesting it may have been a subcutaneous manifestation of B dermatitidis. Further workup for immunodeficiencies has been negative. Six months postoperatively, the patient remains in good health.

Conclusion and Discussion

Blastomycosis dermatitidis infections are not uncommon, but extension into the ear and mastoid is exceedingly rare. Of the few reported cases, most presented as otitis media or potential neoplasm. This case was unique, in that the patient was a healthy male without obvious signs of dissemination who presented with a stenotic ear canal, facial paralysis, and hearing loss with possible extension into the intracranial space and adjacent soft tissue. While the patient’s otalgia and facial paralysis has completely resolved, his hearing is not back to his baseline.

These cases are critical to identify because the reported causes almost all have some degree of permanent hearing loss. Additionally, with demonstrated extension into the retromastoid soft tissue and surrounding muscle, other symptoms and long-term sequelae are possible. When otitis media is refractory to treatment especially in the presence of additional symptoms such as facial paralysis, imaging, tissue culture (including fungal), and biopsy should be considered. While other fungal infections may be more common, B dermatitidis should not be excluded if the patient has a history of B dermatitidis or has lived in or traveled to an endemic region, regardless of immunocompetency. This fungal infection risk is especially high in the setting of an occupational exposure to soil and dust. Identifying these cases quickly is critical to prevent or reduce permanent hearing loss and further damage from local tissue or intracranial invasion.