Cutaneous mucormycosis of the head and neck with parotid gland involvement: first report of a case.

Abstract

Cutaneous mucormycosis is an uncommon, life-threatening, opportunistic fungal infection that is a distinctly different entity from the more frequent although still uncommon rhinocerebral form that is better known to otolaryngologists. We describe what to our knowledge is the only reported case of cutaneous mucormycosis of the face with parotid gland involvement, which occurred in a 56-year-old man. The diagnosis was established by tissue biopsy. The patient was treated with antifungal medications and wide local debridement, including a total parotidectomy with sacrifice of the inferior division of the facial nerve. At the 2-year follow-up, he remained free of disease. Familiarity with the risk factors associated with the development of cutaneous mucormycosis is critical to determining the need for early tissue biopsy to confirm the diagnosis. Generally favorable clinical outcomes are associated with prompt and aggressive medical and surgical therapy.

Introduction

Cutaneous mucormycosis is an uncommon, life-threatening, opportunistic fungal infection caused by organisms of the class Zygomycetes, most commonly those of the genera Rhizopus, Mucor, Rhizomucor, and Absidia. (1-4) Usually preceded by a disruption of the skin barrier of immunocompromised hosts, cutaneous mucormycosis generally affects the extremities; it rarely occurs in the head and neck. Cutaneous mucormycosis is a distinctly different entity from the more frequent although still uncommon rhinocerebral form that is better known to otolaryngologists. Differences between these two infections include their incidences, aggressiveness, and prognoses. While both are considered to be potentially fatal, the rhinocercbral form is associated with greater morbidity and mortality. (3-5)

An accurate estimate of the incidence of cutaneous mucormycosis in the head and neck has been elusive, although several cases have been reported anecdotally. (5-7) Our review of the MEDLINE database yielded only one previously reported case of mucormycosis (otocerebral) with parotid gland involvement, which was identified by Macdonell et al during a postmortem examination. (8) Until now, no case of cutaneous mucormycosis with parotid gland involvement has been reported. In light of its aggressive behavior, cutaneous mucormycosis is an entity with which otolaryngologists must be familiar because only an early diagnosis can provide an opportunity to overcome the high rates of morbidity and mortality with which it is associated.

Case report

A 56-year-old Hispanic-black man with a history of adult-onset diabetes mellitus was found unresponsive in his home. Upon hospital admission, the patient was obtunded but hemodynamically stable and afebrile. A 3 x 3-cm black eschar with an erythematous halo was noted in the central portion of a 7 x 7-cm area of firm indurated skin and subcutaneous tissue overlying the angle of the mandible (figure 1).

[FIGURE 1 OMITTED]

Laboratory studies revealed marked hyperglycemia (>1,300 mg/dl), acidemia (pH: 7.19), leukocytosis, and elevated levels of serum ketones, blood urea nitrogen (BUN), creatinine, and creatine phosphokinase (CPK). A serum amylase level of 450 U/dl (normal: 80 to 180) and a serum lipase level of 4,000 U/L (normal: 150) were documented. These findings were consistent with diagnoses of diabetic ketoacidosis, acute renal failure secondary to rhabdomyolysis, and possible acute pancreatitis.

Vigorous intravenous fluid resuscitation was instituted, along with insulin and broad-spectrum antibiotic therapy. Once the patient's status improved to the point where he could cooperate during an examination, a complete facial paralysis was documented. Trismus was evident, but no intraoral disease was found.

A biopsy analysis of the lesion obtained after admission revealed the presence of nonseptated hyphae branching at right angles, a finding that was compatible with mucormycosis (figure 2). However, an evidently larger fungal load was noted intraductally rather than within the parenchyma of the parotid gland itself. Lyposomal amphotericin therapy was initiated. Operative and photographic consent was obtained. Immediate surgical debridement with wide local skin excision down to the level of the parotid fascia revealed necrotic parotid tissue. The tail of the parotid gland was elevated along with a 2-cm cuff of sternocleidomastoid muscle. Gross involvement of the inferior division of the facial nerve and surrounding parotid parenchyma was noted. A total parotidectomy with sacrifice of the inferior division of the facial nerve was performed. The nonviable inferior portion of the masseter muscle was also excised along with grossly clear margins down to the periosteum of the angle of the mandible (figure 3). The wound was left open to allow for the detection of persistent or recurrent disease during the postoperative period.

[FIGURE 2-3 OMITTED]

Antimicrobial treatment with lyposomal amphotericin was continued, as intraoperative cultures were positive for Rhizopus oryzae. Close serum glucose control was maintained during the postoperative period. Only minimal wound debridement at the bedside was performed. The wound margins remained pink and viable with healthy granulation. Three weeks following the initial procedure, a cervi-cofacial advancement flap was performed to correct the surgical defect (figure 4). Five days later, the patient was discharged from the hospital in stable condition.

[FIGURE 4 OMITTED]

At the 2-year follow-up, the patient remained disease-free (figure 5). Despite the complete facial paralysis, right eye closure was satisfactorily achieved with superior palpebral gold-weight implantation, which was well tolerated.

[FIGURE 5 OMITTED]

Discussion

The etiology, pathogenesis, epidemiology, and treatment of mucormycosis have been extensively reviewed. [2,3,5,9,10]The rhinocerebral form of the disease is a well-recognized although still uncommon occurrence in the head and neck. This form is associated with a uniformly high mortality rate. Other reported areas of head and neck involvement include the trachea, tympanum, mandible, and temporal bone. [11-15]

Invasive mucormycosis is believed to develop as a result of the germination of spores that are in haled or that settle on the skin. Hyphal proliferation occurs in the tissues of an immunocompromised host (classically a diabetic patient), followed by invasion of blood vessels and subsequent thrombosis, infarction, and tissue necrosis. [2,3,9,10] Direct tissue invasion also occurs.[9] As many as 50% of patients who present with mucormycosis have diabetes as an underlying diagnosis. Nearly half of such patients are in diabetic ketoacidosis.[4] The hyperglycemia, acidosis, and vasculopathy associated with diabetes may have predisposing effects on the onset and course of the disease.[9,10]

Primarily affecting the extremities, cutaneous mucormycosis can involve any site along the skin surface. In many affected patients, a predisposing local anatomic factor can be identified, usually an abrasion but in some cases a surgical wound.[4-6,9] Diagnostic suspicion should arise when the first signs of soft-tissue ischemia and necrosis are present. Coexisting systemic disease is less common in cutaneous mucormycosis than it is in other forms of the disease.[5] Despite its association with considerable mortality and long-term morbidity, cutaneous mucormycosis responds better and more rapidly to therapy than does the rhinocerebral form, and therefore its prognosis is more favorable.[5] The better prognosis may be associated in part with the fact that lesions often arise in conspicuous locations, which facilitates early diagnosis and treatment. Moreover, wide resection results in clear margins more readily in cutaneous lesions than in sinonasal lesions. Finally, cutaneous lesions occur at sites relatively distant from the central nervous system.

In the only other published case of parotid gland involvement in mucormycosis (otocerebral), Macdonell et al conjectured that the disease originated in the parotid, spread through the temporal bone, and invaded the pons and cavernous sinus.[8] In that case, evidence of deep tissue involvement was documented in the absence of any compromise of the overlying skin. In our patient, the cutaneous lesion was evident at the time of hospital admission. The presence of an identifiable skin lesion and a clinical course characterized by adequate disease control following prompt and proper surgical, antifungal, and insulin therapy are consistent with the less-aggressive behavior of cutaneous mucormycosis.

We believe that the pathogenesis of the parotid involvement in our patient was secondary to a direct extension from the overlying cutaneous lesion. It is interesting, however, that we noted an evidently larger fungal load intraductally rather than within the parenchyma of the parotid gland itself. This finding might not be anticipated with direct parotid invasion from an overlying skin lesion. One possible explanation for this histopathologic finding is that the intraductal contents provided a favorable microenvironment for the fungal organisms, which preferentially concentrated there. A different explanation is that retrograde invasion of the parotid gland occurred via the parotid duct with secondary involvement of the overlying skin. However, in the absence of any intraoral fungal lesions, this explanation appears to be far less likely. In conclusion, a necrotic skin lesion in an immuno-compromised patient should be viewed with a high index of suspicion as possible cutaneous mucormycosis. Early biopsy of such lesions is essential to confirm the diagnosis. Extensive and rapid surgical debridement, control of underlying disease, and appropriate antimicrobial therapy are mandatory in order to enhance the possibility of cure in these patients.[3,4,6-8,10,16,19]

References

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(3.) Mucormycosis. Ann Intern Med 1980;93:93-108.

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(8.) Macdonell RA, Donnan GA, Kalnins RM, et al. Otocerebral mucormycosis--a case report. Clin Exp Neurol 1987;23:225-32.

(9.) Waldorf AR, Ruderman N, Diamond RD. Specific susceptibility to mucormycosis in murine diabetes and bronchoalveolar macrophage defense against Rhizopus. J Clin Invest 1984;74:150-60.

(10.) Tierney MR, Baker AS. Infections of the head and neck in diabetes mellitus. Infect Dis Clin North Am 1995;9:195-216.

(11.) Andrews DR, Allan A, Larbalestier RI. Tracheal mucormycosis. Ann Thorac Surg 1997;63:230-2.

(12.) Yun MW, Lui CC, Chen WJ. Facial paralysis secondary to tympanic mucormycosis: Case report. Am J Otol 1994; 15:413-14.

(13.) Brown OE, Finn R. Mucormycosis of the mandible. J Oral Maxillofac Surg 1986;44:132-6.

(14.) Gussen R, Canalis RF. Mucormycosis of the temporal bone. Ann Otol Rhinol Laryngol 1982;91:27-32.

(15.) Vessely MB, Zitsch RP III, Estrem SA, Renner G. Atypical presentations of mucormycosis in the head and neck. Otolaryngol Head Neck Surg 1996;115:573-7.

(16.) Umbert IJ, Su WP. Cutaneous mucormycosis. J Am Acad Dermatol 1989;21:1232-4.

(17.) Meyer RD, Kaplan MH, Ong M, Armstrong D. Cutaneous lesions in disseminated mucormycosis. JAMA 1973;225:737-8.

(18.) Maniglia AJ, Mintz DH, Novak S. Cephalic phycomycosis: A report of eight cases. Laryngoscope 1982;92:755-60.

(19.) Herbrecht R. The changing epidermiology of fungal infections: Are the lipid-forms of amphotericin B an advance? Eur J Haematol Suppl 1996;57:12-17.

From the Department of Otolaryngology (Dr. Numa, Dr. Foster, Dr. Wachholz, Dr. Civantos, and Dr. Weed) and the Department of Pathology (Dr. Gomez-Fernandez), University of Miami School of Medicine.

Reprint requests: Donald T. Weed, MD, Department of Otolaryngology, University of Miami, 1475 N.W. 12th Ave. #4037, Miami, FL 33136. Phone: [phone]; fax: [phone]: e-mail: [e-mail]

Originally presented as a poster during the Southern Section meeting of the Triologic Society; Jan. 13-15, 2000; St. Pete Beach, Fla.