A new diagnostic sampling method in pure neural leprosy: the scraping of the myelin sheath☆☆☆

ure Neural Leprosy (PNL) is a form of leprosy characteized by neural involvement without any skin lesions.1 PNL ffects about 3%--10% of patients with leprosy and it can ccur in any spectrum, although it is more frequent in the uberculoid type.2 We present a case of a patient affected y PNL diagnosed through the scraping of myelin sheaths of he ulnar nerve, Ziehl-Neelsen (ZN) staining, and Polymerase hain Reaction (PCR). A 78-year-old man, a professional missioner in the Philipines and Papua New Guinea, has presented sensory loss touch, pain, and temperature) of left foot and pain of eft hand present over a period of 4 years. A physical xamination revealed dorsal flexion deficit of the left foot, uperficial paraesthesia, and dysesthesia of toes associated ith impaired deep sensitivity. In addition, he presented araesthesia and dysesthesia to the IV and V fingers of the eft hand. The left ulnar nerve was palpable and enlarged n the left elbow and no cutaneous lesions were found. he research of Acid-Fast Bacillus (AFBs) in the nasal swab nd the slit skin smears from earlobes and left elbow was egative. Motor and sensory action potential of the left lnar nerve, left peroneal nerve, left anterior and posteior tibial nerves are suggestive of mono-neuritis multiplex. agnetic Resonance Imaging (MRI) of the left elbow showed he enlarged ulnar nerve partially damaged by entrapment ithin the fibro-osseous tunnel. Neurosurgery allowed the ebridement of the ulnar nerve and, at the same time, the craping of the perineural tissue. ZN stain and PCR of the craping were positive for the presence of M. leprae and the iagnosis of tuberculoid leprae with PNL was made. Antibodes against phenolic glycolipid-1 antigen (anti-PGL antibody) ere negative. A therapy based on a combination of three

drugs (rifampicin 600 mg once a month, dapsone 100 mg daily, and clofazimine 300 mg once a month and 50 mg daily) associated with prednisone 25 mg and gabapentin 300 mg (2 cp/die) was started with improvement of symptoms.
To the best of our knowledge, this is the first case of PNL diagnosed through scraping, ZN staining, and PCR test. Scraping is a technique that allows obtaining a clinical specimen rubbing a part of the body, in our case myelin sheaths of a nerve. The surface is scraped with a 15 Bard-Paker blade held at a right angle to the incision. Upon scraping, perineural tissue is obtained and examined by ZN staining and PCR test. Traditionally, diagnostic criteria for the diagnosis of PNL consist of nerve tissue samples obtained out of a nerve biopsy, analysis of PCR, and measure of anti-PGL-1 antibody levels. 3 However, the invasive procedure of nerve biopsy was criticized by Abhishek De et al. because it has a high rate of complications. 4 They proposed a simple technique of FNAC coupled with PCR in a pilot study 4 and they confirmed its efficacy in a 4-year study. 5 In our case, we did not use the technique of FNAC because an invasive procedure, surgery, was required to solve the compression of the ulnar nerve in the cubital tunnel. However, the scraping of the myelin sheath is a simple tissue sampling method during surgical procedures with less risk of nerve damage.

Financial support
None declared.

Authors' contributions
Ilaria Trave: Conception and planning of the study; elaboration and writing of the manuscript; approval of the final version of the manuscript; obtaining, analyzing, and interpreting the data; effective participation in research orientation; intellectual participation in propaedeutic and/or therapeutic conduct of the cases studied; critical review of the literature; critical review of the manuscript.
Alberto Cavalchini: Conception and planning of the study; elaboration and writing of the manuscript; approval of the final version of the manuscript; obtaining, analyzing, and interpreting the data; effective participation in research orientation; intellectual participation in propaedeutic and/or therapeutic conduct of the cases studied; critical review of the literature; critical review of the manuscript.
Gianfranco Barabino: Conception and planning of the study; elaboration and writing of the manuscript; approval of the final version of the manuscript; effective participation in research orientation; intellectual participation in propaedeutic and/or therapeutic conduct of the cases studied; critical review of the literature; critical review of the manuscript.
Aurora Parodi: Conception and planning of the study; elaboration and writing of the manuscript; approval of the final version of the manuscript; obtaining, analyzing, and interpreting the data; effective participation in research orientation; intellectual participation in propaedeutic and/or therapeutic conduct of the cases studied; critical review of the literature; critical review of the manuscript.

Dear Editor,
Lichen nitidus is a relatively rare, chronic, papulosquamous cutaneous disease that is characterized by multiple fleshcoloured shiny, dome-shaped papules, with sizes from 1 to 2 mm, often referred as pinhead-like papules. 1 The crop of the lesions often is asymptomatic; moreover, it sometimes may associate with pruritus. 1 This uncommon condition was described for the first time by Pinkus in 1901. 2 The skin is the primary site involved but the mucous membranes and nails also might be affected. 3 No racial or sex predilection is reported, although the majority of cases appear to arise in children and young adults. 1,4 There are located and generalized forms of lichen nitidus, sometimes described under clinical variants: familiar, actinic, confluent, vesicular, hemorrhagic, palmo-plantaris, mucous, spinulosus and follicularis, keratodermic, perforating or linear. on the abdomen and genitalia, though they can become disseminated. 5 We are adding to the indexed literature the second case of lichen nitidus exclusively located on both axillae.
The patient is a 26-year-old Caucasian man who was seen for evaluation of asymptomatic lesions on the both axillae; the lesions had been present more than 4-years and showed insidious emergence. He denied previous treatment on the lesions or any medication intake preceding the crop of the lesions. On his dermatological exam, discrete or grouped skin-colored, shiny, firm, monomorphic round, and dometopped papules of 1-to 3-mm in diameter were observed on both axillae (Fig. 1).
A skin biopsy was performed from these lesions, and that displayed a lymphohistiocytic infiltrate in a broadened dermal papilla, with a descending growth of the rete ridges surrounding the dermal inflammatory infiltrate in a ''balland-claw'' manner ( Figs. 2 and 3). The overlying epidermis was noted to be unremarkable, and there was no evidence of spongiosis or exocytosis.
The patient was treated with the combination of dexchlorpheniramine 2 mg and betamethasone 0.25 mg t.i.d per os for 10-days, and after thatt he was virtually clear of lesions.
There is only one report of lichen nitidus on axillae. 3 Our patient displayed lesions only in this area, emphasizing the peculiar aspect of our report. Once considered as a tuberculoid reaction, lichen nitidus is currently regarded as a disorder of unknown origin. The differential diagnosis includes lichen planus, psoriasis, verruca plana and