The Podiatry Institute · Created Date: 11/14/2011 4:10:16 PM

CHAPTER 45

MYCETOMA

James H. Morgafi, Ir., D.P.M.

Mycetoma (Madura Foot) is a rate, Tocalized,destructive infection of the skin and subcutaneoustissues. Fascia, muscle and bone may be involved.The result can be a severely disfiguring mass on thesole of the foot making it extremely difficult towalk or wear shoes comfoftably. The condition israrely characterized by severe pain. Two cases ofmycetoma are presented demonstrating the impor-tance of early recognition of this condition to avoidthe chronic result of the disease.

EPIDEMIOLOGY Al\D PATTIOGEIIESIS

The first case of this disease was reported by Gill' inthe Madura district of India in 1842, hence the name"Madura foot." Since then, cases have been reportedacross the world, primarily in rural areas. Two typesof mycetomahaye been identified - eumycetoma andactinomycetoma. Those caused by true fungi aretermed eumycetoma. Pseudallescheria, Madurella,Phialophora, Pyrenochaeta, Aspergillus, Fusarium,and Acremonium species have been isolated in theseinfections.'Actinomycetoma is caused by a group ofaerobic actinomycetes, including species ofActinomadura, Streptomyces, and Nocardia.' Themost common causative organisms in the \TesternHemisphere are Pseudallescheria boydii, Nocardiabrasiliensis, and Actinomadtra madurae.3'a Theseorganisms exist in the soil as saprophltes and aretraumatically introduced into the tissues of the foot viaa splinter, glass, thorn prick, or cut. Males are infectedfive times more than females. The age range of thoseinfected is from 20 to 50 years of age. Farmers in mralareas are the most colrlnon victims of this infection.

CLIMCAL PRESENTATION

The first clinical manifestation of mycetoma is thepresence of a small papular or nodular sub-cutaneous mass on the dorsal or plantar aspectof the foot that grows progressively larger. The actin-omycetoma deveiop at a mote rapid rate than theeumycetoma. The lesions grow larger and eventuallyl'l-rpture or ulcerate forming sinus tracts. Grains of

the infecting organism and surrounding neutrophilsexude from the sinuses. As new adlacent lesionsform, the older, ruptured lesions scar eventuallyresulting in a chronic, swollen, deformed mass ofscar tissue. The infection can spread along fascialplanes and eventually invade muscle, vessels, nerve,and bone. Regional lymphadenopathy can occur;however, hematogenous spread has not beenrepofted.5 The chronic form of mycetoma is seldompainful, however the edematous deformed foot canmake it difficult to wear shoegear.

DIAGNOSIS

Initial diagnosis is usually made from the clinicalappeatance. The triad of indurated edema, multipledraining sinuses with grain-filled purulence andlocation on the foot make for a rather easy diagno-sis.6 However, in the eady stages of development,these lesions may be difficult to differentiate fromany other subcutaneous nodular mass. Aspirationfor culture and sensitivity of the grains includingbacterial (aerobic and anaerobic), fungal, and acidfast stains are helpful indicators. Histologic exami-nation of the grains may aid in identifying theorganism based on the color, size, and stainingcharacteristics of the grains.T Magnetic resonanceimaging (MRI) will often show a multi-chamberedmass. Plain radiographs will only show osseousinvolvement. They should be used to rule out thepresence of a foreign body or osteomyelitis inextensive chronic cases. Surgical biopsy can also beexcellent diagnostic tool.

Differential DiagnosisThe differential diagnosis for mycetoma is extensive.Early lesions can be easily confused with foreignbody inclusion cysts, ganglion cysts, fibromas, coldabscess, thorn granuloma, or any of a number ofbenign or malignant tumors. The chronic form can beconfused with another infection resulting in multipledraining sinuses caused by gram-positive and gram-negative organisms referred to as botryomycosis.z'Chronic osteomyelitis should also be considered.

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TREATMENT

The combined medical and surgical approach has

been the mainstay of treatment for mycetoma.B'e

Surgical excision of the lesions followed by appro-priate antibiosis has consistently produced the lowestrecuffence rates. Antibiotic therapy is of extremeimpoftance in chronic cases as surgical excisionalone has the highest recurrence rates. For treatmentof the eumycetoma, ketaconazole and itraconazoleare used most often. Penicillin, trimethoprim-sul-famethoxazole, dapsone, amikacin, and streptomycinsulfate have been used for treating the actinomyce-toma.2's If recognized eaiy and a clean resection isachieved, then tfuee months of antifungal or sixweeks of antibiotics (depending on the causativeorganism) is usually adequate.

CASE PRESENTATIONS

Case OneA J7-year-old man presented with a three-day his-tory of a "sore knot" on the plantar aspect of theleft foot. He denied any history of trauma or punc-ture wound. The knot was getting warm, red, andextremely tender. Review of the medical historywas significant for cluster headaches and a historyof a draining wound on his right 1eg that was diag-nosed as a brown recluse spider bite. The bitehealed with local wound care and antibiotics. Hedenied taking any medications and had no aller-gies. He smoked one pack of cigarettes per dayand drank one to two beers per week. He workedas a salesma;fi al a local interior design businessand had no history of foreign travel.

Examination revealed a thin, but otherwisehealthy man in no acute distress. He was afebrile andhad stable vital signs. Neurovascular status was withinnormal limits. A firm, mobile, nodular subcutaneousmass measuing 4 centimeters by 2 centimeters was

located proximal to the second, third, and fourthmetatarsal heads on the plantar aspect of the left foot.Minimal Tocalized edema, erythema, and increased

temperature were noted. Plain film radiographsshowed no signs of foreign body or osseous involve-ment. (Fig. 1) Following atibial nerue block of the leftfoot, the mass was aspirated under sterile technique.No aspirate was obtained. Dexamethasone sodiumphosphate (7/2 cc) was injected locally. The patientwas placed on cephalexin 500 mg every six hoursand hydrocodone as needed for pain.

Figure 1. Initial plain film radiographs show no eviclence of foreignbody or bony involvement.

Figure 2. Frontal plane MRI scan deinonstrates a multi-chamberecl clus-ter of increased soft tissue edema without a well-defined abscess.

Figure J. SaEaittal plane MRI scan

232 CHAPTER 45

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Figure ,1. Postoperative clinical photo taken the day after sllrgery. Notethe extensir.e intolvement of the plantar tissues.

Figure 5. Clinical photo taken of the mass beforesurgery,

The patient returned three days later with atwo-day history of increased pain and swelling. Hewas afebrile. The entire foot was edematous, ande{4hema and ecchymosis were noted along theplantar aspect of the arch. No drainage was noted,and there was no sign of ascending cellulitis. Thelesion had doubled in size. Cefazolin 2 mg wasgiven intramuscularly, and the patient was sent fora MRI. The study showed increased soft tissueedema without evidence of abscess. (Figs. 2, 3) Thenext day the patient had no improvement and wasnow experiencing fever and chills. His temperaturewas 100.3'F. The patient was admitted to the localhospital ar1 an infectious disease consult was

obtained. He was placed on ticarcillin-c1ar,.u1anicacid 3.7 mg intravenously every six hours. Hiswhite cell count on admission was 12,800. The nextday his systemic symptoms had resolved. He wasafebrile, and his white cell count was 11,200. Hisfoot now had a localized greenish abscess beneaththe epidermis. There was still no drainage.

An incision and drainage was performed the fol-lowing day. Brownish yel1ow purulence was noted toextend deep to the plantar fascia into the plantar mus-culature. No tendon sheath involvement was noted.The epidermis was separated from the dermis aroundthe periphery of the abscess. There was no malodor.The wound was irrigated and packed open. A statgram stain showed Actinomycetales. Antibiotics werechanged to ampicillin 500 mg intravenously every srxhours. Irrigation and packing of the wound was per-formed daily. The wound was healthy and clean theday following surgery. (Fig. 4). The final culture andsensitivity isolated Nocardia brasiliensis. The patientwas discharged from the hospital three days aftersurgery on trimethoprim-sulfamethoxazole DS twicedaily by mouth and ceftriaxone 2 mg intravenouslyevery day. Home heaith performed local wound carefor three weeks, until the wound was superficial. Thepatient was kept non-weight bearing wrth crutchesfor three weeks. The intravenous antibiotics were dis-continued after five weeks, and the oral antibioticsafter sk weeks. The wound was completely healedby secondary intention after six weeks without recur-rence of infection. FIe had no limrtation of functionand limited scarring.

Case TkoA 45-year-o1d man presented with a seven monthhistory of a mildly tender mass on the plantaraspect of the right foot. He recalled stepping on apiece of glass in his house nine months ago. Thepuncture wound healed uneventfully. The masswas noticed two months later. It was progressivelygrowing larger and more tender. The patient wasunable to run because of the discomfot. Review ofmedical history was unremarkable except as notedabove. He worked as a school principal.

Physical examination showed an apparentlyhealthy man in no acute distress. He was afebrile,and all vital signs were stable. His neurovascularstatus was intact. A firm, noduiar subcutaneousmass measuring 2'/z centimeters by 1 centimeterwas located on the plantal. aspect of the right footjust proximal to the third and fourth metatarsalheads (Fig. 5). There were no signs of infection and

CHAPTER 45 233

no evidence of the previous puncture wound.Minimal tenderness was produced with palpationof the mass. Plain film radiographs showed nosigns of foreign body or osseous involvement. Thepatient was placed in a soft accommodative insoleand prescribed cephalexin 500 mg eyery six hoursfor one week. He was also instructed to applywarm saline compresses twice daily.

He returned a week later with no improve-ment. Following administration of a tibial nelveblock to the right foot, the mass was aspiratedunder sterile technique. Yellowish, thick fluid wasobtained and sent to a local lab for aerobic, anaerobic, and fungal culture and sensitivity. The patientwas prescribed naproxen 500 mg twice daily. Afterone week, the culture was showing growth of a

mold. The patient reported a reduction in pain,however he wanted to have the mass removed insix months, between school years. Two weeks afteraspiration, the culture and sensitivity was positivefor Pseudallescheria boydii, An infectious diseaseconsult was obtained and the patient was placedon itraconazole 200 mg oral suspension twice daily.Five days later the mass was removed under localanesthesia. A transverse incision was used to excisethe mass. The mass was well encapsulated andextended into the plantar musculature. The mass

was excised in toto.(Fig. 6) The incision was closedand dressed. The mass was incised on the backtable, and yellowish thick fluid with granules wasnoted. (Fig. 7)

The patient was kept non-weight bearing forone week with crutches and then allowed weightbearing on the heel for two weeks. Sutures wereremoved after three weeks, and there was noscarring noted. The itraconazole was continued for12 weeks. The patient had no recurrence of thelesion and no hypertrophic scarring. He is nowrunning without pain.

CONCLUSION

Mycetoma is a rare infection of the foot caused byfungal or bacterial organisms. Diagnosis can be diffi-cult in the early stages of the disease prior toulceration and sinus tract formation. Successful aspiration can be a useful tool to aid with the diagnosisin these eady stages. Once a diagnosis of mycetomahas been made, excision of the lesion or incision anddrarnage followed by appropriate antibiosis can resultin a complete cure without recuffence.

Figure 6. Intra-operative photo of the excised mass

Figure 7. Incised mass containing suppurative granules. Note the thickness of the capstrle of the mass,

REFERENCES

1. Gill: India Army Medical Reports. Churchill, London, 1874.

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3. Green WO, Adams TE: Mycetoma in the United States, AmJ ClinPatbol 42:75-91. L964,

4. Lavalle P: "Nlicetomas: La Experiencia Mexicana. ProblemasActuales," in Libro de Resumens ll Simposio lnternaional dt Micetomas,

Taxco, Mexico, 1987.

5. El Hassan AIrl, Mahgoub ES: Lymph node involvement inMycetoma, Trans R Sac Trop Med Hyg 66:765, 7972.

6, Vanbreuseghem R: The early diagnosis of Mycetoma, Dermatol lnt6:123-740. 7967.

7. Mahgoub ES: Mycetoma in Mahgoub ES (ed) Tropical Mycoses

Beerse, Belgir-rm. 1989.8. Morris MI, Gurevitch A. Edwards JE: "Dematiaccae and Agents of

Supedicial Mycoses," in Gorbach SL, Bartlett JG, Blacklow NR(eds') lnfexians Diseases

-WB Saunders, Philadelphia, 1992.

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