History

Fact Explanation
Skin rash Mycetoma also known as mycotic mycetoma is a chronic subcutaneous fungal infection of the skin and soft tissue caused by more than 30 species of fungi or higher bacteria (actinomycotic mycetoma or actinomycetoma). The organism is inoculated into the skin by minor injuries such as cuts. Mycetoma generally presents as single lesion. Commonest site is the foot. The initial lesion is a painless skin lump which grows gradually to involve the underlying muscles or rarely bones. With time an ulcer appears in the middle of the lesion, followed by a pus or grains discharging from it. The lump develops into a large extent that considerable deformity often makes it difficult to walk. Other than that, the lesion is rarely painful, but it often itches or burns. [1,2,3,4,5]
At risk population Although the cases have been reported worldwide, mycetoma is common among individuals (especially males) in their 30s to 50s living in developing countries of tropical and subtropical regions. Individuals with history of trauma, walking barefoot, involve in agricultural work, have poor personal hygiene, poor nutrition and wounds or multiple infections are predisposed to mycetoma. [2,3,5]
References
  1. VAN DE SANDE WW, MAGHOUB EL S, FAHAL AH, GOODFELLOW M, WELSH O, ZIJLSTRA E. The mycetoma knowledge gap: identification of research priorities. PLoS Negl Trop Dis [online] 2014 Mar, 8(3):e2667 [viewed 04 August 2014] Available from: doi:10.1371/journal.pntd.0002667
  2. GARG A, SUJATHA S, GARG J, PARIJA SC, THAPPA DM. Eumycetoma due to Curvularia lunata. Indian J Dermatol Venereol Leprol [online] 2008 Sep-Oct, 74(5):515-6 [viewed 04 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/19052428
  3. CAPOOR MR, KHANNA G, NAIR D, HASAN A, RAJNI, DEB M, AGGARWAL P. Eumycetoma pedis due to Exophiala jeanselmei. Indian J Med Microbiol [online] 2007 Apr, 25(2):155-7 [viewed 04 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/17582190
  4. HOGADE S, METGUD SC, SWOOROOPARANI. Actinomycetes mycetoma. J Lab Physicians [online] 2011 Jan, 3(1):43-5 [viewed 04 August 2014] Available from: doi:10.4103/0974-2727.78564
  5. AFROZ N, KHAN N, SIDDIQUI FA, RIZVI M. Eumycetoma versus actinomycetoma: Diagnosis on cytology. J Cytol [online] 2010 Oct, 27(4):133-5 [viewed 04 August 2014] Available from: doi:10.4103/0970-9371.73297

Examination

Fact Explanation
Initial skin lump Eumycetoma develops as a skin lump initially and grows gradually to a large mass. With time, an abscess develops. The surface skin is scarred and pale. Apart from the foot, upper extremities, eyelids, lacrimal glands, trunk, buttocks, paranasal sinuses, scalp and mandible are rarely affected. [1,2,3]
Tumorous lesion Patients who seek medical attention after many months usually present with very large tumorous lesions. This tumor may cover the most of the foot/ sole making the patient difficult to walk. Secondary bacterial infection is common. [2,4,5]
Sinus tracts The middle of the lesion caves in, ulcerates to make a sinus tract which may secret serosanguineous or seropurulent discharge. It may contain white-to-yellow or black granules and pus. Most of the times multiple sinus tracts may occur in a single lesion. [1,2,3]
Lymphadenopathy Rarely localized tender lymph node enlargement can be observed. [1,3,5]
References
  1. VAN DE SANDE WW, MAGHOUB EL S, FAHAL AH, GOODFELLOW M, WELSH O, ZIJLSTRA E. The mycetoma knowledge gap: identification of research priorities. PLoS Negl Trop Dis [online] 2014 Mar, 8(3):e2667 [viewed 04 August 2014] Available from: doi:10.1371/journal.pntd.0002667
  2. GARG A, SUJATHA S, GARG J, PARIJA SC, THAPPA DM. Eumycetoma due to Curvularia lunata. Indian J Dermatol Venereol Leprol [online] 2008 Sep-Oct, 74(5):515-6 [viewed 04 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/19052428
  3. CAPOOR MR, KHANNA G, NAIR D, HASAN A, RAJNI, DEB M, AGGARWAL P. Eumycetoma pedis due to Exophiala jeanselmei. Indian J Med Microbiol [online] 2007 Apr, 25(2):155-7 [viewed 04 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/17582190
  4. HOGADE S, METGUD SC, SWOOROOPARANI. Actinomycetes mycetoma. J Lab Physicians [online] 2011 Jan, 3(1):43-5 [viewed 04 August 2014] Available from: doi:10.4103/0974-2727.78564
  5. AFROZ N, KHAN N, SIDDIQUI FA, RIZVI M. Eumycetoma versus actinomycetoma: Diagnosis on cytology. J Cytol [online] 2010 Oct, 27(4):133-5 [viewed 04 August 2014] Available from: doi:10.4103/0970-9371.73297

Differential Diagnoses

Fact Explanation
Cutaneous Tuberculosis Cutaneous tuberculosis (TB) is essentially an invasion of the skin by Mycobacterium tuberculosis, the same bacteria that cause TB of the lungs (pulmonary TB). Cutaneous TB is a relatively uncommon form of extrapulmonary TB (TB infection of other organs and tissues). Even in countries such as India and China where TB still commonly occurs, cutaneous outbreaks are rare. Direct infection of the skin or mucous membranes from an outside source of mycobacteria results in an initial lesion called the tuberculous chancre. The chancres are firm shallow ulcers with a granular base. They appear about 2-4 weeks after mycobacteria enter through broken skin. [1]
Syphilis An infectious venereal disease by Treponema pallidum (spirochete). The primary route of transmission is through sexual contact; it may also be transmitted from mother to fetus during pregnancy or at birth, resulting in congenital syphilis. Presentation of syphilis varies and mimics several diseases. So it is describes as four different stages: primary, secondary, latent, and tertiary. Symptoms of syphilis begin with a painless but highly infectious sore on the genitals, or sometimes around the mouth. Secondary symptoms, such as a skin rash and sore throat, then develop. Around a third of people who are not treated for syphilis will develop tertiary syphilis. At this stage, it can cause serious organ damages. [2]
Squamous Cell Carcinoma Squamous cell carcinoma (SCC) is a common type of skin cancer. It is derived from squamous cells, the flat cells that make up the outside layers of the skin, the epidermis. These cells are keratinising i.e., they produce keratin, the horny protein that makes up skin, hair and nails. Invasive SCC refers to cancer cells that have grown into the deeper layers of the skin, the dermis. Invasive SCC can rarely metastasize. Invasive SCCs are usually slowly-growing, tender, scaly or crusted lumps. The lesions may develop sores or ulcers that fail to heal. Most SCCs are found on sun-exposed sites, particularly the face, lips, ears, hands, forearms and lower legs. [3]
Yaws A prevalent, infectious and nonvenereal treponemal disease and is caused by Treponema pallidum pertenue. The initial stage is characterized by the appearance of small, painless bumps on the skin that group together and grow until they resemble a strawberry. A crispy and crunchy rash that covers arms, legs, buttocks and/or face is a late sign. [4]
References
  1. THAKUR BK, VERMA S, HAZARIKA D. A clinicopathological study of cutaneous tuberculosis at Dibrugarh district, Assam. Indian J Dermatol [online] 2012 Jan, 57(1):63-5 [viewed 04 August 2014] Available from: doi:10.4103/0019-5154.92685
  2. PATTON ME, SU JR, NELSON R, WEINSTOCK H, CENTERS FOR DISEASE CONTROL AND PREVENTION (CDC). Primary and secondary syphilis--United States, 2005-2013. MMWR Morb Mortal Wkly Rep [online] 2014 May 9, 63(18):402-6 [viewed 25 July 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/24807239
  3. AWAN BA, ALZANBAGI H, SAMARGANDI OA, AMMAR H. Scalp squamous cell carcinoma in xeroderma pigmentosum. N Am J Med Sci [online] 2014 Feb, 6(2):105-6 [viewed 04 August 2014] Available from: doi:10.4103/1947-2714.127754
  4. MITJà O, ŠMAJS D, BASSAT Q. Advances in the diagnosis of endemic treponematoses: yaws, bejel, and pinta. PLoS Negl Trop Dis [online] 2013, 7(10):e2283 [viewed 25 July 2014] Available from: doi:10.1371/journal.pntd.0002283

Investigations - for Diagnosis

Fact Explanation
Microscopic examination Etiological agent can be identified by microscopic examination. The colour of the grains may suggest the likely diagnosis; black grains suggest a fungal infection, minute white grains suggest nocardia and red grains are due to Actinomadura pelletieri. Larger white grains or yellow-white grains may be fungal or actinomycotic in origin. [1,2,3]
Polymerase chain reaction (PCR) Species-specific diagnosis can be made by polymerase chain reaction and DNA sequencing. [2,3]
Fine-needle aspiration FNAC FNAC of lesions using special stains may be useful for the diagnosis. [1,2,3,4]
X-ray The extent of the tumor into the underlying bones can be identified by X-rays. A radiograph of the heel may reveal extensive loculated lytic areas of destruction within the body of the calcaneum and other affected bones with a typical "honeycomb" appearance. Radiography shows infiltration of soft tissue, associated more or less with bone resorption. [3,5]
CT scan Multislice CT is highly useful for assessing osteoarticular damage. It shows a mass isodense to muscle, heterogeneous, which can contain denser rounded nodules that infiltrate the skin and the subcutaneous fat tissues. The affected muscles are thickened or partially destroyed. Enhancement is heterogeneous and moderate. CT is more sensitive than MRI for detecting osteoperiosteal damage and for early visualization of small cortical lesions. [3,5]
MRI scan MRI is the most helpful examination for a positive diagnosis and for staging mycetoma, which appears, in comparison to muscle, as a discrete hyperintense signal with T2 weighting and as a hypo- or isointense signal with T1 weighting. Contrast uptake after gadolinium injection is moderate and heterogeneous; the signal from the mycelial granules remains clearly hypointense. The characteristic appearance is that of an infiltrating mass made up of small cavities, hyperintense on T2 weighting, and circumscribed by hypointense fine partitions containing central dots, hypointense on all sequences and creating a nearly pathognomonic sign, called the “dot-in-circle”, especially useful when clinical, microbiological and histological findings are not determinative. [3,5]
Biopsy Biopsy samples can be taken from small abscess or from the sinus tract. It may show extensive granulation tissue containing abscesses. Gram-negative septate hyphae are also visible. Eosinophilic material may be seen deposited around the granule. Actinomycotic grains contain very fine filaments. [1,2,3]
References
  1. VAN DE SANDE WW, MAGHOUB EL S, FAHAL AH, GOODFELLOW M, WELSH O, ZIJLSTRA E. The mycetoma knowledge gap: identification of research priorities. PLoS Negl Trop Dis [online] 2014 Mar, 8(3):e2667 [viewed 04 August 2014] Available from: doi:10.1371/journal.pntd.0002667
  2. AFROZ N, KHAN N, SIDDIQUI FA, RIZVI M. Eumycetoma versus actinomycetoma: Diagnosis on cytology. J Cytol [online] 2010 Oct, 27(4):133-5 [viewed 04 August 2014] Available from: doi:10.4103/0970-9371.73297
  3. CAPOOR MR, KHANNA G, NAIR D, HASAN A, RAJNI, DEB M, AGGARWAL P. Eumycetoma pedis due to Exophiala jeanselmei. Indian J Med Microbiol [online] 2007 Apr, 25(2):155-7 [viewed 04 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/17582190
  4. HOGADE S, METGUD SC, SWOOROOPARANI. Actinomycetes mycetoma. J Lab Physicians [online] 2011 Jan, 3(1):43-5 [viewed 04 August 2014] Available from: doi:10.4103/0974-2727.78564
  5. BOUZIANE M, AMRISS O, KADIRI R, ADIL A. The role of computed tomography in the exploration of Madura foot (pedal mycetoma). Diagn Interv Imaging [online] 2012 Nov, 93(11):884-6 [viewed 04 August 2014] Available from: doi:10.1016/j.diii.2012.05.003

Management - Specific Treatments

Fact Explanation
Antifungal therapy In vitro antifungal sensitivity of organisms is not necessarily correlated with that of in vivo. So, the decision making regarding the most suitable antibiotic remains difficult. Single or combination treatment should be tried. Itraconazole and Ketoconazole are most commonly used drugs in mycetoma. Streptomycin injections, Oral cotrimoxazole, Amikacin, Dapsone and Rifampicin can be tried in case of mycetoma. [1,2,3,4]
Surgical treatment Surgical resection with a wide surgical margin or Surgical debulking can be used in combination with the medical therapy. Rarely, amputation of the affected limb has to be done. [2,3,4]
References
  1. AFROZ N, KHAN N, SIDDIQUI FA, RIZVI M. Eumycetoma versus actinomycetoma: Diagnosis on cytology. J Cytol [online] 2010 Oct, 27(4):133-5 [viewed 04 August 2014] Available from: doi:10.4103/0970-9371.73297
  2. GARG A, SUJATHA S, GARG J, PARIJA SC, THAPPA DM. Eumycetoma due to Curvularia lunata. Indian J Dermatol Venereol Leprol [online] 2008 Sep-Oct, 74(5):515-6 [viewed 04 August 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/19052428
  3. HOGADE S, METGUD SC, SWOOROOPARANI. Actinomycetes mycetoma. J Lab Physicians [online] 2011 Jan, 3(1):43-5 [viewed 04 August 2014] Available from: doi:10.4103/0974-2727.78564
  4. VAN DE SANDE WW, MAGHOUB EL S, FAHAL AH, GOODFELLOW M, WELSH O, ZIJLSTRA E. The mycetoma knowledge gap: identification of research priorities. PLoS Negl Trop Dis [online] 2014 Mar, 8(3):e2667 [viewed 04 August 2014] Available from: doi:10.1371/journal.pntd.0002667