Mycosis fungoides with CNS involvement: neuropsychiatric manifestations and complications of treatment with intrathecal methotrexate and whole-brain irradiation.

The case of a 42-year-old Caucasian male with CNS dissemination of mycosis fungoides is described. This patient developed prominent mental status changes and subtle neurologic signs, and was treated with intrathecal methotrexate and whole-brain irradiation.

Benign and malignant forms of erythroderma: cutaneous immunophenotypic characteristics.

In order to determine if immunohistologic features are useful in distinguishing benign from malignant types of erythroderma, we studied the immunophenotype of lesional T cells in 20 patients (8 mycosis fungoides/Sézary syndrome, 12 benign) and found them to be generally similar. In all cases, the majority of T cells were Leu-1+, Leu-4+, and Leu-5+, as is typical of mature T cells. Although in most cases a majority of Leu-3+ (helper/phenotype) T cells were present, in 2 there was a majority of the Leu-2+ (cytotoxic/suppressor) subset and in 12 others, a significant minority (20%-40%) of these cells. Low percentages of Leu-2+ cells (less than or equal to 10%), resulting in high Leu-3+/Leu-2+ ratios, did not distinguish benign from malignant erythroderma. Leu-8 antigen deficiency was common in both mycosis fungoides/Sézary syndrome and benign cases (62% vs 75%, respectively). In contrast, Leu-9 antigen deficiency was present in only one patient in each group. The lack of combined Leu-8/9 antigen deficiency in our patients may be due to a heavy inflammatory T cell component, obscuring the antigen deficiencies seen in most nonerythrodermic mycosis fungoides cases. We conclude that immunophenotypic studies with the use of the current antibody panel show many similarities between benign and malignant forms of erythroderma, as well as some minor differences that may prove diagnostically useful if corroborated by future studies.

Merkel cell tumor of the thigh.

This case of a Merkel cell carcinoma is unusual due to the occurrence of the tumor on the thigh; most Merkel cell tumors have been found on the sun-exposed region of the head and neck. Histologically, the nodule was composed of sheets of uniform, poorly differentiated cells with a high nuclear to cytoplasmic ratio. Electron microscopy revealed perinuclear filaments, scattered dense core granules, and complex, interdigitating processes within cytoplasmic membranes. Treatment consisted of surgical excision of the tumor with a wide margin.

Poikilodermatous mycosis fungoides and atrophic large-plaque parapsoriasis exhibit similar abnormalities of T-cell antigen expression.

We studied the immunohistologic findings of skin biopsy specimens from 21 patients with poikiloderma (14 with mycosis fungoides [MF] and seven with atrophic large-plaque parapsoriasis [ALPP]). Both types of poikiloderma were similar with regard to T-cell antigen expression. In each case, most T cells expressed the CD4+ (helper/inducer) phenotype and lacked Leu-8 antigen. T cells were also deficient in Leu-9 antigen in most cases (MF, 11/14 [79%]; ALPP, 4/7 [57%]). These T-cell antigen deficiencies are similar to those described previously in various types of MF and indicate that such deficiencies are common in minimally infiltrated, patch-stage MF lesions. Because combined Leu-8/Leu-9 antigen deficiencies are uncommon in inflammatory skin diseases, our findings are consistent with the view that ALPP is an early form of MF, as had been suggested previously by results of clinicopathologic studies.

Pharmacokinetics of topically applied radiolabeled retinoids in hairless mouse epidermis and dermis after single applications.

The retention of tritium-labeled all-trans-retinoic acid (RA), 13-cis-retinoic acid (13-cis-RA), aromatic retinoid, and arotinoid ethyl ester in the epidermis and dermis of hairless mice was measured up to 24 h following a single topical application in an acetone vehicle. The radioactivity in the tissues was extractable with chloroform:methanol, and the identities of the radioactive species extracted were confirmed as retinoids using thin-layer chromatography. All the retinoids were absorbed into the skin rapidly. After an initial period of distribution and penetration (lasting for about 1 h) the amount of the applied retinoid remaining in the epidermis and dermis decreased more slowly, obeying first order (exponential) decay kinetics. Both the arotinoid and the aromatic retinoid persisted for longer in the epidermis than equivalent doses of RA or 13-cis-RA. The half-lives of the retinoids in the dermis tended to be longer than in the epidermis, except for the arotinoid. Aromatic retinoid persisted for longest in the dermis with a half-life of 11 h.