The histopathology of the skin in the ichthyosiform erythroderma associated with classical Conradi-Hunermann syndrome has been rarely described. Skin biopsies from 2 infants with the classical features of Conradi-Hunermann syndrome including ichthyosiform erythroderma contained hyperkeratosis, dilated ostia of pilosebaceous structures, and calcium salts in the stratum corneum detectable with special stains. An unusual feature of one case was dilatation of acrosyringeal structures. We hypothesize that dilatation of acrosyringeal structures is analogous to the plugging noted in pilosebaceous units. Taken together, the ichthyosiform erythroderma of Conradi-Hunermann has a distinctive histologic appearance.

An histologically typical clear cell acanthoma was identified forming a cystic structure. The finding of clear cell acanthoma within a cyst is histologically unique.

We described here a case of a 43-year-old male who developed confluent and reticulated papillomatosis (CRP). The patient was found to be slightly obese and had no family history of such eruption. Numerous small red-brown erythemas were scattered over a wide area of the back and, in many areas, the erythemas coalesced and formed a reticular pattern. The eruptions appeared 10 days prior to the initial visit to our outpatient clinic. The Parker-KOH preparation of scraped scales revealed numerous round and budding non-clustering cells and no mycelial elements. Histological examination showed subtle papillomatosis and sparse perivascular lymphohistiocytic infiltrations. Periodic acid schiff stain showed a few spores in the stratum corneum. Topical application of 2 % ketoconazole cream produced complete resolution of the eruption in 7 days. The course and histological findings of our patient suggest the eruptions were developing CRP lesions. Application of topical antifungal agents appears to be a beneficial initial treatment for early CRP lesions.

Cutaneous protothecosis developed in a 63-year-old Japanese female. The patient had a long history of steroid use for bronchial asthma. A tender, swollen, erythematous plaque with white papules covered the dorsal aspect of the patient's right hand. Histopathological examination showed typical protothecosis with numerous "mulberry-like" sporangia positive for periodic acid-Schiff stain. The pathogen was identified as Prototheca wickerhamii. After a 6-week course of 150-200mg/day itraconazole (ITCZ) therapy, the patient's culture was negative for P. wickerhamii. No recurrence was seen after 12 weeks of ITCZ therapy. This case of protothecosis and those of 16 patients are summarized. All the patients had lived in mid-to southern Japan.Only 12 cases of protothecosis treated with ITCZ have been reported in the literature; 8 of these cases were cured with ITCZ therapy alone. In cases treated with ITCZ at no more than 100mg/day, medication was typically needed for 2 months; most of the cases treated with ITCZ at 200mg/day were successfully cured within 2 months. A 2-month course of ITCZ at 200mg/day appears to be adequate treatment for human protothecosis.