Zosteriform Cutaneous Leiomyoma. Satisfactory Treatment With Oral Doxazosin

[A clinical case of piloleiomyoma]

The article describes a clinical case of a benign tumor from smooth muscle cells - piloleiomyoma. The incidence of leiomyoma in the skin is 3-5% of all leiomyomas. A 27-year-old patient applied to a medical institution with complaints about an intradermal formation in the ear region that occurred repeatedly within 5 months after surgical treatment. After the first surgical intervention, the patient was consulted in various medical organizations, where the following diagnoses were made: «nodular fasciitis», «smooth muscle tumor without signs of malignancy» and «non-epithelial spindle cell neoplasm». According to ultrasound examination, the formation with dimensions of 11×9×5 mm reached the mastoid process of the temporal bone and was characterized by increased internal blood flow. After surgical removal of the neoplasm, taking into account the difficulties of differential diagnosis, an immunohistochemical study was conducted. An accumulation of smooth muscle cells was detected in the surface layers of the dermis under the epidermis by the immunohistochemical study with the use of the marker SMA. A study on CD34 protein revealed a high density of blood capillaries and the absence of its expression in smooth muscle cells. The proliferative index (Ki-67) and mitotic activity (PHH-3) of cells was also studied. The index of proliferative activity was less than 2%, mitoses were isolated. Thus, the results of immunohistochemical study proved the conclusion of piloleiomyoma.

Doxazosin selectively potentiates contraction to serotonin via 5-HT₂A receptors in longitudinal muscle strips of the rabbit gastric body

The aims of this study were to examine the effects of doxazosin on contractile responses to 5-hydroxytryptamine (5-HT), carbachol, and histamine, and to compare them with those of prazosin, alfuzosin, and terazosin, and then characterize a pharmacological profile of the 5-HT-induced contractile response using preparations of isolated longitudinal muscle strips from the rabbit gastric body. The results from these preparations showed that the contraction response to 5-HT, but not to carbachol or histamine, was found to be dose-dependently potentiated by doxazosin and its enantiomers. The specific potentiation effect on 5-HT was not observed in the preparations that were treated with prazosin, terazosin, or alfuzosin. The contractile response to 5-HT and its potentiation by doxazosin were not affected by treatment with phenoxybenzamine. However, 5-HT-induced contraction was competitively antagonized by nefazodone (with pA₂ value of 8.64 ± 0.17), and was almost completely inhibited by treatment with indomethacin. In conclusion, doxazosin, but not prazosin, alfuzosin, or terazosin, selectively potentiates 5-HT-induced contraction in the rabbit gastric body strips via an α₁-adrenoceptor-independent mechanism, without chiral recognition of its enantiomers. Additionally, the contraction to 5-HT was found to be mediated via 5-HT(₂) receptors, and was similar to PGs synthesis in the preparations.