Mycetoma is a chronic, slowly progressive, debilitating subcutaneous infection caused by the traumatic inoculation of either true fungi (producing eumycetoma, B47.0) or filamentous bacteria of the order Actinomycetales (producing actinomycetoma, B47.1) — most commonly through a thorn prick, wood splinter, or contaminated soil puncture wound affecting the foot, leg, or hand in tropical and subtropical regions. Despite their identical clinical appearance, the two forms are biologically and therapeutically distinct: eumycetoma is caused by true fungi such as Madurella mycetomatis and treated with prolonged antifungal agents (itraconazole); actinomycetoma is caused by aerobic actinomycetes — most commonly Nocardia brasiliensis, Actinomadura madurae, and Streptomyces somaliensis — and treated with antibiotics (trimethoprim-sulfamethoxazole ± amikacin). The underlying pathological mechanism involves the organism forming compact, organized microcolonies surrounded by a host-derived cement matrix to create macroscopic grains (also called granules or sclerotia), which elicit surrounding granulomatous and suppurative inflammation, progressive fibrosis, and, in advanced cases, osteomyelitis and bone destruction. The pathognomonic clinical triad — (1) localized subcutaneous swelling, (2) draining sinus tracts, (3) extrusion of colored grains from the sinuses — differentiates mycetoma from other causes of tropical lymphedema, chromoblastomycosis, sporotrichosis, and botryomycosis; grain color is a critical clinical clue: black grains suggest Madurella species (eumycetoma), while white-to-yellow or red grains may indicate either form, requiring culture or histopathology for definitive etiologic diagnosis. When the etiologic form is genuinely undocumented, B47.9 (mycetoma, unspecified) is appropriate, though this should prompt a clinical query given that treatment selection depends entirely on the distinction between fungal and bacterial forms.
“mushroom,” “fungus” — the primary Greek root for all things fungal; the genitive stem mykēt- is the source of the combining form mycet-
-et-
Greek genitive stem -ēt- from mykēs → mykētos
Linking element derived from the genitive stem of mykēs — bridges the root to the suffix; present because the compound draws on the full declined stem mykēt- rather than the nominative mykes
Noun-forming suffix — “tumor,” “swelling,” “mass,” “result of a process” — in medical terminology, indicates a neoplastic or tumor-like growth; here used descriptively for the mass-like swelling characteristic of the disease
The anatomical site designation “Madura foot” (the original lay name) was coined in 1842 by British surgeon John Gill, who described the condition in Madura (now Madurai), a city in Tamil Nadu, India — the geographic focus of earliest documented cases. The formal medical term mycetoma was introduced in 1860 by Henry Vandyke Carter, a British physician and anatomist working in India, who published the first systematic description and derived the term from Greek mykētos (“of the fungus”) + -oma (“tumor”) — literally “fungal tumor” or “tumor of fungal origin.” Carter coined the name before the causative organisms were fully characterized, leading to later discovery that some cases are actually bacterial (actinomycetes), making the myc- prefix technically imprecise for actinomycetoma. The root myc- / myko- (“fungus”) connects mycetoma to the entire -myco- root family: mycology* (study of fungi), onychomycosis* (fungal infection of the nail), mycobacterium* (waxy fungus-like bacterium), actinomycosis* (ray-fungus disease), and dermatomycosis* (fungal infection of the skin). The suffix -oma is similarly productive: granuloma* (grain-like tumor), hematoma* (blood swelling), lipoma* (fat tumor), carcinoma* (crab-like cancer), and neuroma* (nerve tumor).
🔀 ALIASES / ALTERNATE TERMS
Mycetomatous(adjective form — appears in clinical collocations such as “mycetomatous swelling,” “mycetomatous grain,” “mycetomatous sinus tract”)
*Madura foot (the original and most common lay/clinical term; geographically named for Madura (Madurai), India, where the disease was first described in 1842; used interchangeably with mycetoma pedis when the foot is involved)
Maduromycosis(historical clinical synonym used in the early 20th century; now largely obsolete but still encountered in older literature and some international references)
Eumycetoma(the fungal form of mycetoma — caused by true fungi, most commonly Madurella mycetomatis; characterized by black or white grains; requires antifungal therapy; coded B47.0)
Actinomycetoma(the bacterial form — caused by aerobic actinomycetes such as Nocardia, Actinomadura, and Streptomyces; characterized by white, yellow, pink, or red grains; requires antibiotic therapy; coded B47.1)
Madura disease(regional synonym — used interchangeably with Madura foot/mycetoma in clinical and epidemiological literature, especially in South Asian and African contexts)
Mycetoma pedis(anatomically specific Latin term for mycetoma of the foot — the most common site of infection, accounting for approximately 70% of cases)
Black grain mycetoma(descriptive clinical subtype of eumycetoma — caused by melanin-producing fungi such as Madurella mycetomatis; grain color guides empiric therapy before culture results)
White grain mycetoma(descriptive clinical subtype — may be eumycetoma or actinomycetoma depending on causative organism; requires histopathology or culture for definitive distinction)
Neglected tropical disease (NTD)(WHO classification — mycetoma was officially added to the WHO list of neglected tropical diseases in 2016; relevant for public health reporting and international coding contexts)
🔗 RELATED TERMS
Eumycetoma — the fungal subtype of mycetoma (B47.0); caused by true fungi, most commonly Madurella mycetomatis (black grain) and Pseudallescheria boydii (white grain); managed primarily with itraconazole and surgical debulking; tends to be more localized and fibrotically encased than actinomycetoma
Actinomycetoma — the bacterial subtype of mycetoma (B47.1); caused by aerobic filamentous bacteria; more invasive and rapidly progressive than eumycetoma; responds well to antibiotic combination therapy (TMP-SMX ± amikacin)
Grains / granules — the pathognomonic microscopic aggregates of the causative organism surrounded by a polysaccharide-protein cement matrix; their color, size, texture, and internal structure on histopathology are the primary diagnostic features that distinguish eumycetoma from actinomycetoma and identify the causative species
Sinus tract — a hallmark of established mycetoma; a pathological channel connecting an abscess cavity to the external skin surface through which pus and grains are discharged; multiplies as the disease progresses
Osteomyelitis — bone infection; occurs in advanced mycetoma when the inflammatory process erodes through subcutaneous tissue into underlying bone, causing lytic lesions visible on imaging; dramatically worsens prognosis and may necessitate amputation
Chromoblastomycosis — a closely related subcutaneous fungal infection presenting as verrucous, warty, nodular skin lesions (not as swelling with sinus tracts); caused by dematiaceous (dark-pigmented) fungi; important differential for mycetoma — distinguished by absence of sinus tracts and grains
Sporotrichosis — a subcutaneous mycosis caused by Sporothrix schenckii; key differential for mycetoma — presents as lymphocutaneous nodules along lymphatic channels rather than a localized swelling with grains; coded B42.x
Botryomycosis — a rare chronic bacterial infection (usually Staphylococcus aureus) that produces gram-positive granules in a sinus-tract pattern mimicking mycetoma; distinguished by absence of filamentous organisms on histopathology
Nocardia — the most common genus of actinomycetes causing actinomycetoma globally; also causes pulmonary nocardiosis and disseminated infection in immunocompromised hosts; weakly acid-fast gram-positive filamentous bacterium
Actinomadura madurae — the second most common cause of actinomycetoma worldwide; produces large, white, multilobular grains; named after Madura (Madurai), India — the same geographic origin as the disease name
Madurella mycetomatis — the most prevalent causative fungal species in eumycetoma globally, particularly in sub-Saharan Africa; produces pathognomonic black grains due to melanin production
Itraconazole — the mainstay antifungal agent for eumycetoma treatment; requires prolonged courses (months to years); therapeutic drug monitoring (TDM) via itraconazole drug assay (80189) is recommended to ensure adequate serum levels
CODING CORNER
🏥 ICD-10-CM CODES
Mycetoma (B47) — Etiologic Form Specificity Required
Associated / Comorbid Codes — Common Coding Companions
Code
Description
B47.0
Eumycetoma (fungal mycetoma — true fungal form; includes Madura foot due to fungi; Maduromycosis)
B47.1
Actinomycetoma (bacterial mycetoma — caused by aerobic actinomycetes; includes Nocardia, Actinomadura, Streptomyces species)
Personal history of other infectious and parasitic diseases (for resolved/treated mycetoma; follow-up coding)
🔧 COMMON CPT CODES (Mycetoma-Related Diagnosis & Treatment)
CPT Code
Description
87102
Culture, fungi (mold); with presumptive identification of isolates (primary fungal culture for eumycetoma diagnosis — initial isolation of causative mold)
87107
Culture, fungi; identification by immunologic method, each organism, mold (add-on identification for Madurella or Pseudallescheria species following positive 87102)
87149
Identification by nucleic acid (DNA or RNA probe), each organism (molecular species identification — DNA probe for definitive eumycetoma organism ID)
87153
Identification by DNA sequencing, each isolate (when standard probes cannot identify the causative mold; used for rare or novel species)
87070
Culture, bacterial; any other source except urine, blood or stool, with isolation and presumptive identification (initial culture for actinomycetoma — identifies Nocardia, Actinomadura, Streptomyces)
11106
Punch biopsy of skin and when performed, adjacent subcutaneous tissue; first lesion (primary skin biopsy for grain collection and histopathological diagnosis)
Surgical pathology, gross and microscopic examination; Level IV (tissue examination of mycetoma biopsy — standard pathology processing for grain identification)
10021
Fine needle aspiration biopsy, without imaging guidance; first lesion (FNA for grain aspiration from a sinus tract or fluctuant nodule for direct microscopy)
73721
Magnetic resonance imaging, any joint of lower extremity; with contrast material(s) (MRI foot/ankle — primary imaging for assessing bone invasion and surgical planning in pedal mycetoma)
73630
Radiologic examination, foot; complete, minimum of 3 views (X-ray foot — used for initial and serial assessment of osteolytic lesions and cortical bone destruction)
Debridement, subcutaneous tissue (includes epidermis and dermis, if performed); first 20 sq cm or less (surgical debulking of eumycetoma — reduces fungal load to improve antifungal penetration)
Debridement, muscle and/or fascia; first 20 sq cm or less (deeper debridement when mycetoma has invaded muscle or fascial planes)
11044
Debridement, bone; first 20 sq cm or less (debridement extending to bone — used for mycetoma osteomyelitis; highest-complexity debridement level)
28820
Amputation, foot; at metatarsophalangeal joint, hallux (distal foot amputation for extensive or refractory mycetoma involving the forefoot and hallux)
80189
Drug assay, itraconazole (therapeutic drug monitoring — ensures adequate serum itraconazole levels during prolonged eumycetoma treatment; guides dosing adjustments)
⚠️ Coding Note: The single most critical coding decision for mycetoma is distinguishing B47.0 (eumycetoma — fungal) from B47.1 (actinomycetoma — bacterial), as these two subtypes require completely different treatment regimens and have significantly different prognoses; defaulting to B47.9 (unspecified) should be a last resort and always warrants a provider query when grain morphology, culture, or histopathology results are in the chart. Sequencing follows standard infectious disease guidelines: the mycetoma code is the principal diagnosis when it drives the admission; when osteomyelitis has developed as a complication, add M86.9 (or the most site-specific osteomyelitis code available) as an additional diagnosis — inpatient profee coders should note that documented osteomyelitis in mycetoma carries CC or MCC weight under MS-DRG v43.1 and must not be omitted. A high-yield undercoding alert: actinomycetoma (B47.1) is frequently miscoded as B47.9 (unspecified) or even coded under the actinomycosis code family (A42.89) — these are distinct conditions; actinomycetoma is caused by aerobic actinomycetes (Nocardia, Actinomadura), while actinomycosis is caused by anaerobic Actinomyces species; query trigger phrases include “Nocardia in culture,” “Actinomadura species,” “white/red/yellow grains on wound culture,” or “eumycetoma” vs. “actinomycetoma” documented by infectious disease.
For CPT, note that 87107 and 87153 are add-on identification codes that require a primary fungal culture (87102) as the parent code; do not report the ID codes without the initial culture code. Debridement codes 11042-11044 are reported by depth (subcutaneous, muscle/fascia, then bone) and by surface area (first 20 sq cm, then add-on codes for each additional 20 sq cm); multiple depth levels at the same session require separate codes for each distinct tissue layer debrided.
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