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Here, a case of a rare epithelial sheath neuroma (ESN) is reported. A 49-year-old white female presented with a 5 mm solitary, slightly raised, erythematous, itchy papule on her right upper back. The clinical impression was consistent with an inflamed nevus. The patient had no past medical history of malignancy or a family history of neurofibromatosis. There was no prior trauma, surgical procedures, or skin disease at the site. After excision, the patient has had no recurrence at the surgery site during a 4-months follow-up period. ESN is characterized by enlarged nerve fibers ensheathed by a sometimes keratinized squamous epithelium located in the superficial dermis where large nerves are not normally found. It is believed to be a benign neoplasm and simple excision is curative. The histologic differential diagnosis of ESN is presented, and possible mechanisms of its pathogenesis are discussed. It is important for the pathologist and dermatologist to be cognizant of this lesion to prevent misdiagnosis of perineural invasion.

Background Examination of multiple stool specimens per patient to rule out parasitic infection continues to be recommended in the literature. Attractive alternatives have been proposed, such as examination of a single specimen, but data to support their use have been inconclusive. Methods We reviewed the results of comprehensive stool ova and parasite examinations performed during a 1-year period to determine the incremental value of examining >1 specimen. Next, we implemented rejection criteria, allowing analysis of only a single specimen in most cases, and studied the impact of the change by reviewing data from a subsequent year. Results Prior to implementation of rejection criteria, 91% of parasites were detected in the first specimen submitted, although many clinical evaluations (72%) involved the submission of only 1 stool specimen. When at least 3 specimens were submitted, the sensitivity of examining the first in the series was 72%. Even the latter sensitivity provides negative predictive values of approximately 98%, approximately 97%, approximately 95%, or approximately 93% when the prevalence of parasites among those tested is 5%, 10%, 15%, or 20%, respectively. Examination of additional specimens after examination of the first specimen that yielded a positive finding revealed previously undetected parasites in only 10% of cases. After the application of rejection criteria, the parasite detection rate did not change significantly. Conclusions Comprehensive examination of a single stool specimen is sufficient for most patients, when the prevalence of infection among the tested population is up to 20%. Rational use of the stool ova and parasite examination relies on communication between clinician and laboratory, and retention of deferred specimens in case examination of additional specimens is clinically warranted.

It has been shown that normal mode ruby laser pulses (694 nm) are effective in selectively destroying brown or black pigmented hair follicles in adult Caucasians. This study investigated how the various stages of the hair follicle growth cycle influence follicle destruction by ruby laser treatment, using a model of predictable synchronous hair growth cycles in the infantile and adolescent mice. A range of ruby laser pulse fluences was delivered during different stages of the hair growth cycle, followed by histologic and gross observations of the injury and regrowth of hair. Actively growing and pigmented anagen stage hair follicles were sensitive to hair removal by normal mode ruby laser exposure, whereas catagen and telogen stage hair follicles were resistant to laser irradiation. Selective thermal injury to follicles was observed histologically, and hair regrowth was fluence dependent. In animals exposed during anagen, intermediate fluences induced nonscarring alopecia, whereas high fluences induced scarring alopecia. The findings of this study suggest treatment strategies for optimal laser hair removal.

Laser-induced fluorescence excitation and resolved emission spectra have been observed from the arylmethyl radicals, triphenylmethyl, diphenylmethyl, diphenylchloromethyl, and diphenylethyl. The free-jet-cooled radicals exhibit spectra with rich but well resolved vibrational structure, some of which is likely attributable to hindered twisting of the phenyl rings. Precise frequencies for the origins of the electronic transitions as well as fluorescence lifetimes for these radicals are reported.

Control of the transport of molecules into the nucleus represents a key regulatory mechanism for differentiation, transformation, and signal transduction. Permeabilization of the nuclear envelope by physical methods can have applications in gene therapy. Laser-induced pressure transients can produce temporary aqueous pores analogous to those produced by electroporation and that the cells can survive this procedure. In this study, we examine the role of the pressure transients in creating similar pores in the nuclear envelope.The target human peripheral blood mononuclear cells in a 62 microM 72 kDa fluoresceinated dextran solution were exposed to the pressure transients generated by laser ablation. An in vitro fluorescence confocal microscope was used to visualize and quantify the fluoresceinated dextran in the cytoplasmic and nuclear compartments.In contrast to electroporation, the pressure transients could deliver 72 kDa fluoresceinated dextrans, which are normally excluded by the nucleus, across the nuclear envelope into the nucleus. In addition to creating pores in the plasma membrane, temporary pores were also created in the nuclear envelope following exposure to pressure transients.The production of temporary nuclear pores could provide a unique resource for drug-delivery and gene therapy.

Background: During laser-assisted hair removal, sebaceous glands closely associated with hair follicles might also be affected. Objective: We investigated the effect of the long-pulsed ruby laser on sebaceous glands. Methods: Sebum excretion rates (SERs) of 16 subjects were measured quantitatively by means of sebum-absorbent tape and analyzed by means of image analysis techniques on laser-treated sites, compared with adjacent untreated areas. Evaluation was done at an average of 9 months (range, 4.5 to 12 months) after the last treatment. Histologic examinations were performed on 3 representative subjects before treatment, immediately after treatment, and 9 months after the last treatment. Results: Significant increases in SERs were observed in 11 of 16 subjects (68.75%). Three subjects (18.75%) showed lower SERs, whereas 2 subjects (12.5%) demonstrated no difference in SERs between treated and untreated areas. Biopsy specimens showed an apparent reduction in sebaceous gland size. Specimens taken immediately after laser irradiation revealed sporadic damage to sebaceous glands. Conclusion: In some patients a variable but statistically significant increase in sebum excretion occurs 4 to 12 months after ruby-laser hair removal treatment at high fluences. A reduction in sebaceous gland sizes on laser-treated areas was observed. We hypothesize that decreased resistance to sebum outflow may explain this result, following miniaturization or absence of hair shaft after ruby laser treatment. Further study is needed to assess mechanisms for this interesting response. (J Am Acad Dermatol 1999;41:176-80.)

It has been shown that using normal mode ruby laser pulses (694 nm) is an effective method of selectively destroying brown or black pigmented hair follicles in adult Caucasians (Grossman et al, 1996). The pigment, melanin, contained within the dark hair follicles acts as a target for light absorption when exposed to a well characterized range of wavelengths (Anderson and Parrish, 1981). Based on principles of selective photothermolysis, exposure to carefully chosen wavelength and pulse duration characteristics result in preferential absorption by the target pigment and sufficient heating to cause localized cellular destruction (Anderson and Parrish, 1983).