Surgical specimens were obtained from a patient who had had life-threatening paracoccidioidomycosis 5 years previously. Residual lesions were found in the mesenteric lymph nodes; there were areas of caseous necrosis separated from the surrounding tissue by a fibrous capsule made of connective tissue. Abundant P. brasiliensis cells, many of which appeared degenerated, were observed in the necrotic material. Primary isolation was possible only.under the microaerophilic conditions offered by fluid media kept stationary at 36 °C. Cultures in solid media were obtained after serial passages and gradual accommodation of the strain to aerobic incubation. It is apparent that P. brasiliensis yeast cells can become accustomed to reduced oxygen tension in the tissues. In this way, they are able to withstand the passing of time without completely losing their viability.Paracoccidioides brasiliensis, the etiologic agent of paracoccidioidomycosis, is isolated regularly from pathological specimens on a diversity of solid media incubated under aerobic conditions at either 37 °C or room temperature I-3, 4, 6]. For primary isolation, liquid media are seldom used 1-3, 4, 6-1. However, Pedroso found that the semianaerobic environment offered by liquid cultures in tall columns was advantageous for the primary isolation of the yeast phase [5]. The latter report, however, is not very detailed, thus hindering complete assessment of the finding.Recent experimental studies revealed that the yeast-like cells of this fungus can accommodate to the microaerophilic conditions present in stationary liquid cultures [9]. Long periods of latency are known to occur in human paracoccidioidomycosis [2] and we therefore wondered whether dormancy of P. brasiliensis, similar to that seen in vitro, might occur in vivo.We recently had the opportunity to study material from walled-off lesions obtained at surgery from a patient who had experienced active paracoccidioidomycosis 5 years previously. This report presents the results of the pertinent mycological and histopathological studies.
CASE REPORTIn December 1975, a 17-year-old man presented because of cramping, progressive abdominal pain of approximately 3 months' duration. Two weeks before admission he developed vomiting and for the last 5 clays he had been unable to have bowel movements and his urine output had diminished. Examination showed