Year : 2007 | Volume
: 11 | Issue : 2 | Page : 66--69
Mucormycosis of maxillary sinus
Pooja Aggarwal1, Susmita Saxena1, Vishal Bansal2,
1 Department of Oral Pathology, Subharati Dental College, Meerut, India
2 Department of Oral and Maxillofacial Surgery, Subharati Dental College, Meerut, India
Department of Oral and Maxillofacial Pathology, Subharati Dental College, Meerut
Mucormycosis is a fungal infection commonly affecting structures in the head and neck, such as air sinuses orbits and the brain. Common predisposing factors include diabetes and immunosuppression. One such case of mucormycosis associated with diabetes mellitus reported to Subharati Dental College, Meerut.
|How to cite this article:|
Aggarwal P, Saxena S, Bansal V. Mucormycosis of maxillary sinus.J Oral Maxillofac Pathol 2007;11:66-69
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Aggarwal P, Saxena S, Bansal V. Mucormycosis of maxillary sinus. J Oral Maxillofac Pathol [serial online] 2007 [cited 2017 Nov 20 ];11:66-69
Available from: http://www.jomfp.in/text.asp?2007/11/2/66/37385
Mucormycosis is the name ascribed to infections caused by usually nonseptate fungi belonging to the class Zygomycetes (Phycomycetes).  Historically, Paltauf  is credited with the first histologic description of generalized mucormycosis in a 52-year-old patient. Since this report appeared in 1885, opportunistic infections caused by fungi of the order Mucorales (genera Rhizopus, Mucor and Absidia) have been recognized, in association with diabetes, hematologic malignant disease, immunosuppressive therapy, thermal burns and surgery.  Mucormycosis rarely affects otherwise healthy people. 
The most common presentation of mucormycosis is maxillary and orbital cellulitis in a person with inadequately controlled diabetes with ketoacidosis. , The term Phycomycetes is often used because it refers to a class of bread molds, of which the Mucorales is one family. 
Since mucormycosis occurs infrequently, it may pose a diagnostic and therapeutic dilemma for those who are not familiar with its clinical presentation. The purpose of this paper is to draw attention to the clinical presentation and pathogenesis of mucormycosis and to emphasize the need for high index of suspicion in its diagnosis and management.
A 70-year-old male patient reported with bad breath and pus discharge from upper left region of jaw since one month.
Patient gave the past medical history that he was diagnosed as a case of diabetes mellitus 12 years ago, for which he did not receive proper treatment. Three months ago, he was brought to the Emergency Department in an unconscious state. He was diagnosed as a case of diabetic ketoacidosis with renal failure (Arterial blood gas (ABG) - metabolic ketoacidosis, blood sugar - 400 mg/dl, urine dextrose strip ++++, urinary ketone - positive) and was treated accordingly. He gave history of development of the oral lesion at the same time.
On intraoral examination, left posterior maxillary alveolar bone was exposed and covered with necrotic slough. Lesion extended from left maxillary premolar area to left maxillary second molar area [Figure 1]. Radiographic examination revealed, opacification of left maxillary sinus [Figure 2],[Figure 3].
Incisional biopsy was taken from left maxillary alveolar ridge. The specimen obtained for histopathological examination consisted of necrotic tissue and mucosa from margin of the lesion.
Histology of the received specimen showed stratified squamous epithelium which was ulcerated with intraepithelial split formation; underlying connective tissue showed numerous minor salivary glands, ducts and muscle tissue. Large amounts of necrotic tissue were evident with cellular degeneration and debris [Figure 4]. Fungal hyphae were seen with neutrophil infiltration and generalized chronic inflammatory cell infiltrate within connective tissue. Hyphae were aseptate, branched and resembled mucormycosis. Areas of hemorrhage were present [Figure 5]. These histopathological features were suggestive of fungal infection (mucormycosis) with tissue necrosis. Periodic Acid Schiff staining revealed PAS-positive hyphae. [Figure 6].
Mucormycosis is a rare fulminating opportunistic fungal infection caused by a fungus of the order Mucorales. , These fungi are ubiquitous, found throughout the world on fruit and bread, in air and in soil, where they exist as saprophytes. , Although the fungi and spores of Mucorales show minimal intrinsic pathogenicity towards normal persons, they can initiate aggressive and fulminating infection in the immunocompromised host. 
Depending on the immunological status of the host, the disease may manifest in six different ways depending on the affected site: rhinocerebral, pulmonary, cutaneous, gastrointestinal, central nervous system or miscellaneous. For example, patients with diabetes mellitus usually have the rhinocerebral and pulmonary forms of disease. Patients who are malnourished usually have the gastrointestinal forms of disease.  High fatality with diabetes is due to the angioinvasive character of the Mucor, thereby causing thrombosis of blood vessels and tissue necrosis.  Mucorales are ferrophilic fungi. Acidosis reduces the binding of iron to transferrin; in turn, available free iron helps in proliferation of the Mucorales. 
In the diabetic ketoacidotic patient, there is a high incidence of mucormycosis caused by Rhizopus oryzae, also known as Rhizopus arrhizus, because they produce the enzyme ketoreductase, which allows them to utilize the patient's ketone bodies. It is also likely that the hyperglycemia stimulates fungal growth, and the diabetic reduction in chemotaxis and phagocytic efficiency permit these otherwise innocuous organisms to proliferate. 
Mucormycosis of head and neck region results from inhalation of airborne spores. In the nasal mucosa, germination ensues and the hyphal elements penetrate, by direct extension or through vascular channels, the paranasal sinus, orbit brain and occasionally even the eye.  In a study done by Ferry et al.  and by Yohai et al.  on mucormycosis cases, they reported sinus involvement in 69% and 79% respectively.
Destructive lesions of the palate and maxilla should suggest a peripheral T-cell lymphoma (formerly termed midline lethal granuloma), nasopharyngeal carcinoma and tertiary syphilis. Some might be concerned about a Wegener's granulomatosis, but this disease is limited to the palatal soft tissue and does not necrose the palate or maxilla. 
Fungal sinusitis generally affects only debilitated patients.  The Phycomycetes and Aspergillus organisms are common opportunistic pathogens in the milieu of immunologically compromised patient;  so mucormycosis should also be differentiated from aspergillosis. Radiographically in aspergillosis, radiopaque concretions may be identified whereas mucormycosis shows opacification of sinus,  as also seen in the present case.
Suspicion of mucormycosis requires a CT scan of the maxilla orbits and brain. In particular, evidence of intracranial brain abscesses and orbital extensions is critical. Sinus and orbital extensions are recognized by membrane or periosteal thickenings as well as bony disruption. 
Routine blood studies will show a leukocytosis in the 12,000-20,000/L range and usually a left shift (Schilling shift to the left, indicative of immature neutrophil). If the patient is diabetic, a full workup of serum glucose, electrolytes, blood chemistries and blood gases is required. 
Serological assays for Mucor antigens have been developed. However, these assays remain investigational.  Confirmation of the diagnosis is best obtained with a tissue specimen from the junction of necrotic and nonnecrotic tissue. Staining with methenamine silver or a PAS stain, in addition to H and E, will often show the organism in vessel walls or nerve bundles. 
Mucormycosis is appropriately diagnosed histologically when broad, irregularly shaped, nonseptate hyphae with right angle branching are seen invading the tissue with H and E; but are better visualized with PAS or silver strains. , They are found mostly in areas adjacent to clinical necrosis, especially within necrotic vessel walls.  Frequently, arterial invasion causes infarction.  The tissue infected by the organisms usually shows non-specific acute and chronic infl mmation with granulation tissue and necrosis but granulomas are not seen. 
Spores are black or brown and smooth in appearance,  but microscopically spores are more prominent in aspergillosis than in mucormycosis.  Speciation requires culture of fungus and the advice of a mycologist with a special interest in the Mucorales. ,,
Medical management alone is not effective because of poor drug delivery to the infection due to extensive vascular thrombosis.  Mucormycosis is a severe tissue-loss and life-threatening disease. Aggressive control of the underlying disease and aggressive debridement are needed. Patients should undergo a resection-type debridement as soon as they are physiologically stable. The subsequent wound is best left open for care and irrigation but may be obturated with a removable prosthesis-obturator to support speech and feeding. 
Amphotericin B therapy should also be initiated as soon as possible. It is usually given in Dextrose 5% in water intravenously at a dose of 1.0-1.5 mg/kg daily. A lipid formulation of amphotericin B can maintain high blood levels with lower toxicity and may be more efficacious.  Adjunctive hyperbaric oxygen should also be used when available. Evidence now shows a better prognosis with the use of hyperbaric oxygen, probably because it reverses the hypoxia in local tissues and enhances neutrophil- and macrophage-killing ability.  Magnetic resonance imaging of the head is useful in determining the extent of disease involvement, so that surgical margin can be planned. 
The prognosis is directly related to the severity of the underlying disease, the extent of the disease when treatment begins and the aggressiveness of the treatment. Death is a common outcome of the disease (30-50%). Hence the general approach is to treat early, aggressively and with all modalities available. 
Mucormycosis is an uncommon frequently fatal fungal infection, which rarely arises in otherwise healthy people. An underlying disease, frequently diabetes mellitus, is almost always present. It appears stereotypically in different anatomic sites - namely, paranasal, rhino-orbital, rhino-cerebral, cerebral, pulmonary and gastrointestinal area - and in the soft tissue of the extremities. It can also appear as disseminated disease. Tissue invasion by the hyphae of mucormycosis must be seen microscopically to establish the diagnosis, but culture is required to identify the fungal species involved.
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