Leukoplakia is associated with increased risk of oral cancer and is considered a premalignant lesion. Retinoids, particularly 13-cis retinoic acid, can frequently reverse leukoplakia. However, these drugs have considerable toxicity and are not suitable for large-scale use in the prevention of oral cancer. Beta-carotene is a naturally occurring, nontoxic carotenoid with biologic properties that suggest that it might be efficacious against oral leukoplakia. In 1986, we began a randomized study of 13-cis retinoic acid (1 mg/kg/d) versus beta-carotene (30 mg/d) in leukoplakia. However, owing to the marked differences in toxicity between the two compounds outlined in the consent form, 11 of the initial 16 eligible patients refused to participate unless they were "guaranteed" beta-carotene. Therefore, the study design was changed to a phase II trial of beta-carotene in which the compound was given daily for 3 months. Responding patients were continued for another 3 months of treatment. All lesions were examined histologically at entry. Responses were monitored by bidimensional measurements and photography done at entry, then monthly while on treatment and at study completion. Twenty-four evaluable patients were treated, and 17 had major responses (two complete, 15 partial), a response rate of 71% (95% confidence limits, 53% to 89%). There was no significant toxicity requiring drug discontinuation or dose reduction. These results indicate that beta-carotene has substantial activity in oral premalignancy. Because of its lack of toxicity, it is an excellent candidate for a preventive agent for oral cancer.

A case of zygomycosis caused by Apophysomyces elegans in a diabetic, obese female is described. The fungus gained entry into the body through injury to the skin, penetrating the keratin, epidermis, and dermis. Hyphal angioinvasion was observed. Fungal elements invaded the subcutaneous fat, skeletal muscle fibers, nerves, and large blood vessels, resulting in the spread of the infection. The rapidity with which A. elegans invaded the blood vessels left no choice except amputation of the leg to stop the spread of the infection. This zygomycetous fungus closely resembles Absidia corymbifera. It is distinguished by its prominent campanulate apophyses. In its gross colony characteristics and failure to sporulate on routinely used media it resembles Saksenaea vasiformis.

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A 27-year-old man with a 6-year history of allergies developed nasal polyps that occluded his nose and prevented visual examination beyond the nasal vestibules. Histological examination of the polyps and bony tissue revealed septate, dematiaceous hyphae invading the bone trabeculae. A dematiaceous fungus was isolated in pure culture from the diseased tissue. Detailed mycological examination of the isolate showed that it produced numerous, distinctive poroconidia from erect, geniculate, sympodial conidiophores. The conidia were straight and cylindroellipsoidal, had 8 to 13 distosepta, and had protruding hila. The outer cell walls of the conidia, which were initially smooth, became unevenly roughened on aging. Comparison with other Exserohilum species revealed that the isolate represented an undescribed species; it is named Exserohilum mcginnisii sp. nov.

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