Clinical Characteristics (Localized Form)

The clinical lesions start with a small papule or ulcer, usually on a lower limb, but sometimes on the hands or elsewhere in the arms. Satellite lesions start if the patient scratches. Progress is very slow, over many months or even years. Eventually they either become smooth or verrucous, tumoral or nodular, with cauliflower-like warty swellings which spread over the years. They may be mistaken for hyperkeratosis or squamous cell carcinoma (Fig. 6.32). When secondary infection occurs there is often a foul discharge. The fungal infection may form large papillomatous growths involving much of the limb. The nodular pattern becomes tumorous, large, rough, and ulcerating. The fungi can be squeezed from the parakeratotic masses. The secondary infection spreads along lymphatics, with satellite lesions: eventually there will be marked fibrosis and so much lymphatic blockage that there can be elephantiasis. There is seldom any regional lymphadenopathy, nor should there be discharging sinuses, although this can occasionally happen after aspiration.

It is emphasized that this a predominantly skin and subcutaneous infection but direct spread to bone has occurred and resulted in chronic osteomyelitis. In phaeohyphomycosis, particularly when due to Cl. trichoides, cerebral abscesses may be the commonest complication: there have also been patients with infection of paranasal sinuses. In chromoblastomycosis, cerebral abscesses are rare. (Note: Cl. trichoides may have, or soon have, a different name.)

Imaging Diagnosis

The cerebral lesions are indistinguishable from any other brain abscess. Plain radiographs of the skull or paranasal sinuses are usually not helpful: CT and MR scanning can demonstrate the brain lesion, which will contrast enhance.

In the peripheral skeleton there are no characteristic changes: the pattern is that of chronic osteomyelitis with one or more central foci.

Summary

For the mycologist, chromoblastomycosis is a fertile source of debate and the allocation and reallocation of fungi into different species. For the radiologicist, it is important to know that this infection can exist, and that it is one of the many causes of cerebral abscess. For the clinician, chromoblastomycosis is a very difficult infection to treat, particularly late in the disease. For the patient, it is a chronic, slowly progressive affliction which seems never to go away and will eventually cause much pain and disability.