Concurrent plexiform ameloblastoma and COVID-19-associated mucormycosis of the maxilla.

Introduction

The recent second wave of COVID-19 in India has been devastating due to the extremely high morbidity and mortality rate [1]. One of the most conspicuous and frequently observed morbidities was an invasive mucormycotic infection of the rhinocerebral and lung region [2]. During the second wave of COVID-19, the incidence was so high in the Indian population that the government declared it a medical emergency.

Ameloblastoma is a common benign odontogenic locally aggressive neoplasm of the jawbone [3]. Although it is most commonly seen in the mandibular posterior region, cases have been also reported in the maxillary bone. Among the various histologic variants, follicular and plexiform are the most common types reported in the literature [4]. Due to its painless and invasive nature, ameloblastoma is sometimes diagnosed as accidental pathology on radiological examination [4]. In this paper, we present an accidentally discovered case of plexiform ameloblastoma in COVID-19 associated maxillary mucormycosis.

Case report

A 74-year-old male patient reported typical symptoms of COVID-19 (fever, cough, shortness of breath, loss of taste, and smell sensation). On RT-PCR, a confirmatory E-gene and RdRp genes were detected with a cycle threshold value of 28. The patient also gave a history of recently diagnosed uncontrolled diabetes mellitus. High-resolution CT thorax showed multiple patchy areas of peripheral and central bilateral ground-glass density with intra-lobular interstitial thickening at various lobes (right upper, right middle, right lower, left upper, and left lower) with a CT score of seven. Other hematological and biochemical parameters were within normal range and HIV (I and II), Hepatitis B, and C tests were negative. The patient was admitted to the ICU for 5 days and given Inj. Remdesivir IV (loading dose of 200 mg, followed by 100 mg daily for 11 days), IV infusion Methylprednisolone (80 mg/day in 240 mL saline at 10 mL/h for 18 days), and Inj. Dexamethasone (4 mg twice daily was given for 12 days). The patient got discharged after the 15th day of admission.

After 10 days patient reported back with progressively increasing pain and swelling on the left side of the face. On extra-oral examination, a diffuse swelling was reported on the left side of the face. Intra-oral examination revealed chronic generalized periodontitis and loosening of teeth of the upper left side of the maxilla. A mild swelling was reported in the associated mucobuccal fold with redness and tenderness. Cone Beam Computed Tomographic examination showed soft tissue thickening with left maxillary sinus along with thinning and break in the continuity of anterior, medial, and posterior-lateral walls. A lytic lesion was reported with sparse trabeculae in the maxillary alveolar bone extending from midline to the third molar (Fig. 1 A). Buccal and lingual cortical plates showed irregular bone destruction. A provisional diagnosis of mucormycosis was made and confirmed using a KOH smear. Inj. Amphotericin B 300 mg/day was started and surgical excision was planned.

Fig. 1

(A) The cone-beam computed tomographic view showing an osteolytic lesion extending over the left side of the maxilla. (B) A well-defined radiolucency is evident (yellow arrow) surrounded by irregular diffuse osteolysis. (C) Photomicrograph showing central stellate reticulum-like cells (yellow arrow) and peripheral low columnar cells arranged in a plexiform pattern. (D) Other bits of tissues showing the non-septated and branched hyphae distributed evenly in the stroma. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

Surgical excision of the maxilla was performed through an intra-oral approach under general anesthesia. The affected bone was necrosed and hence was retrieved in multiple pieces. The surgical site was sutured by approximating the healthy mucosa of the oral cavity. Inj. Amphotericin B 300 mg/day was continued for one month.

The microscopic examination of the excised specimen showed numerous non-sepatated hyphae with and without branching arranged in groups as well as in isolation in and around the granulation and necrotic tissues (Fig. 1D). Intriguingly, a few bits of the excised specimen showed the features typical of plexiform ameloblastoma with central stellate reticulum-like cells and peripheral low columnar to tall columnar cells (Fig. 1C). We then retrospectively searched for the radiological evidence of ameloblastoma and could able to locate a radiolucent circular lesion (Fig. 1B). Based on the aforementioned features a final diagnosis of invasive sinonasal mucormycosis with concomitant plexiform ameloblastoma was made.

Discussion

To date, only two cases of association of ameloblastoma with mucormycosis have been reported in the literature [5], [6]. Molero et al. in 1985 reported an invasive rhinocerebral mucormycosis involving an eyeball with the accidental finding of ameloblastoma [5]. In the second case, You et al. reported a recurrent case of mandibular ameloblastoma with non-invasive histopathologically inactive mucormycosis in a liver transplant patient [6]. The present case is the first of its kind as plexiform ameloblastoma was an accidental finding in COVID-19 related mucormycosis of the maxilla.

Mucormycosis is an opportunistic fungal infection most commonly seen in an immunocompromised state such as HIV, organ transplant, corticosteroid therapy, uncontrolled diabetes mellitus, leukemia, etc. [7]. The mucormycosis in the present case could be the manifestation of the use of corticosteroid drugs and diabetes mellitus. However, the dysregulation of immune status due to auto-antibody developments against some vital immunological components could also be responsible for the development of mucormycosis in the present case [8]. Due to unavailability of the resources, we could not perform the titer of such autoantibodies to rule out the primary cause of immunosuppression.

Ameloblastoma is an asymptomatic lesion and is sometimes reported as an accidental finding on radiographs [3], [4]. This behavior is mainly because of the painless nature and invasion through the marrow spaces. Hence, it is quite conceivable that in the present case the ameloblastoma was already existing and was detected accidentally during mucormycosis management. To the best of our knowledge, no other accidental odontogenic pathology has been reported during the surgical management of COVID-19-associated mucormycosis. Oral pathologists involved in the diagnosis of mucormycosis should be vigilant for the possible presence of accidental pathologies.

Funding source

The authors received no specific funding for this work.

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.