[Chronic cutaneous infiltration with abscess and fistula formation. A type of clinical course in atypical mycobacteriosis].

BACKGROUND: Cutaneous lesions of atypical mycobacteriosis are very rare in Western Europe. Both the slow disease progression and the rather unspecific clinical appearance of the chronic infiltration render cutaneous mycobacteriosis a diagnostic challenge. In this communication, we present an uncommon, biphasic course of a cutaneous atypical mycobacteriosis. CASE REPORT: A 3-year-old child was referred to our institution due to submandibular cutaneous infiltration together with subcutaneous abscess formation. There was no carious lesion or other odontogenic potential source of infection. First-line therapy was incision of the abscess and local curettage to obtain a specimen for histologic and microbiologic evaluation, which revealed atypical mycobacteria. In spite of local curettage, only partial remission of the cutaneous infiltration was achieved. When the child was readmitted 9 months later, the lesion had progressed to a scrofulosis-like appearance even though specific antibiotic treatment had been administered. Complete surgical excision of the affected skin and extirpation of the respective lymph node and fistula was performed as second-line therapy. Complete remission was achieved without further adjuvant treatment. DISCUSSION: Our case demonstrates the problems that may arise with this rare type of mycobacterial infection. In all probability, scratch artifacts due to atopic dermatitis provided the source/entry of the infection in this specific case. Both histopathologic findings and clinical appearance were suggestive of classic cutaneous tuberculosis (tuberculosis cutis colliquativa), although it was in fact an atypical mycobacteriosis. Furthermore, obstinate persistence after minor surgical intervention and even after specific (triple) antibiotic treatment illustrates the difficulties of limited, minimally invasive treatment.