Histopatología de la uña

Physiology of the nail apparatus: Surgical consequences

Knowledge of nail physiology is mandatory to understand nail pathologies, and to know what to repair and what to expect from your repair. Unfortunately, nail physiology in humans is not completely understood. However, there are some data that have been validated and must be known before treating patients. The nail plate is mostly made of keratins. It is produced solely by the nail matrix. The nail bed is mostly responsible for nail pate adhesion. At the hyponychium, the plate loses its adherence. The hyponychium is the first barrier of defense preventing bacteria and fungi from invading the subungual area. All these structures, along with the nail folds, are responsible for the orientation of nail-plate growth. However, many questions, such as whether to replace the nail plate at end of procedure, remain open.

Subungual Melanocytic Lesions: Key Clinical and Pathologic Concepts and Biopsy Techniques

Both dermatologists and pathologists sometimes find daunting the evaluation of melanonychia (especially subungual melanocytic lesions) because of the fear of performing nail surgery due to the risk of dystrophy, difficulties processing and interpreting nail biopsy specimens, and a general lack of experience in the field. Nevertheless, mastery of nail biopsy techniques, correct processing and orientation of specimens, and familiarity with the histologic particularities of the nail apparatus can attenuate the undoubted complexity and facilitate the tasks involved. Longitudinal excision is the biopsy technique that ensures the simplest histologic interpretation, and it is associated with a low risk of nail dystrophy when performed correctly. Clinical and epidemiological data are crucial. Subungual melanoma in childhood, for instance, is very rare and even lesions with atypical clinical and/or histologic features are probably benign. The presence of suprabasal melanocytes and other findings that would suggest malignancy at other sites are considered normal in the nail apparatus. Subungual melanoma shows a lentiginous pattern in the early stages of disease, and detection of an inflammatory infiltrate accompanying atypical lentiginous subungual lesions would appear to be one of the first diagnostic findings.

Ultrasound characterization of the nail bed in patients with systemic lupus erythematosus

OBJECTIVE

To characterize the ultrasound findings of the nail plate and nail bed in systemic lupus erythematosus (SLE) and its association with nail dystrophy.

METHODS

Thirty-two SLE patients, 36 patients with osteoarthritis (OA) and 20 healthy individuals were studied. High-frequency linear ultrasound was performed in nails of the second to fifth fingers in all participants. Disease activity (SLEDAI-2K index), accrued organ damage (SLICC/ACR index), autoantibody profile, and Raynaud's phenomenon were also assessed in SLE patients.

RESULTS

Nail bed thickness in SLE patients was higher than in healthy individuals (1.25 ± 0.31 mm vs 1.17 ± 0.29 mm; P = 0.01) but lower than in OA (1.39 ± 0.37 mm; P < 0.001), while nail plate thickness was similar among groups. Nail dystrophy was found more frequently in SLE and OA than in healthy individuals. SLE patients with nail dystrophy were older than their counterparts with no dystrophy (39.4 ± 10.4 years vs 27.8 ± 5.6 years; P = 0.004), although nail dystrophy showed no association with SLICC/ACR, SLEDAI-2K, nail bed vascularity, or autoantibodies.

CONCLUSIONS

Nail bed in SLE patients is thicker than in healthy individuals but thinner than in OA patients. Nail dystrophy in SLE is associated with advanced age, but not with accrued organ damage, disease activity, Raynaud's phenomenon, or DIP synovitis assessed by ultrasound.

Subungual Melanocytic Lesions: Key Clinical and Pathologic Concepts and Biopsy Techniques

Both dermatologists and pathologists sometimes find daunting the evaluation of melanonychia (especially subungual melanocytic lesions) because of the fear of performing nail surgery due to the risk of dystrophy, difficulties processing and interpreting nail biopsy specimens, and a general lack of experience in the field. Nevertheless, mastery of nail biopsy techniques, correct processing and orientation of specimens, and familiarity with the histologic particularities of the nail apparatus can attenuate the undoubted complexity and facilitate the tasks involved. Longitudinal excision is the biopsy technique that ensures the simplest histologic interpretation, and it is associated with a low risk of nail dystrophy when performed correctly. Clinical and epidemiological data are crucial. Subungual melanoma in childhood, for instance, is very rare and even lesions with atypical clinical and/or histologic features are probably benign. The presence of suprabasal melanocytes and other findings that would suggest malignancy at other sites are considered normal in the nail apparatus. Subungual melanoma shows a lentiginous pattern in the early stages of disease, and detection of an inflammatory infiltrate accompanying atypical lentiginous subungual lesions would appear to be one of the first diagnostic findings.

Nail Matrix Pathology in Cronkhite-Canada Syndrome: The First Case Report

Cronkhite-Canada Syndrome (CCS) presents with gastrointestinal polyposis and the triad of cutaneous abnormalities including nail dystrophy, alopecia, and hyperpigmentation of the skin. The etiology is not well understood. The histology of skin lesion in CCS has not been routinely described. Especially, the nail matrix pathology has not been reported. In this study, the authors report the nail matrix pathology in a patient with CCS. Interestingly, the histologic evaluation revealed matrix hypergranulosis. Because matrix hypergranulosis is commonly found in several inflammatory nail diseases, this discovery points out that an inflammatory process is probably one of the important pathogeneses in CCS.

Relation Between Nail Consistency and Incidence of Ingrown Toenails in Young Male Runners

BACKGROUND

This study examines the possible influence of factors such as nail shape and consistency, sex, and sports activity on the development of the most common nail disorders in a population of young people.

METHODS

The nail plates of 140 young people (66 females and 74 males) were studied. Of these 140 participants, 72 were runners who trained more than 10 hours a week and competed regularly, and 68 did not habitually do any sports activity. Nail shape, consistency, and disorders were examined, taking into account the sex of the participants and their sports activity.

RESULTS

A hard nail consistency is more frequent in runners (74.4%) than in people who do no sports activity (25.6%). In contrast, a soft nail consistency is more prevalent in participants who do no sports activity (70%) than in runners (30%). It was also shown that onychocryptosis is related to sex, as females had a higher prevalence of this nail disorder (57.8%, P = .016). However, young male runners showed the highest and most significant percentage of the presence of onychocryptosis (74.1%; P = .002).

CONCLUSIONS

Sports activity by young male runners whose nails have a hard consistency seems to be directly related to the high incidence of onychocryptosis in this population.

Processing dermatological biopsies

Dermatological biopsies can be obtained from many anatomic areas and fulfill a variety of diagnostic roles. Due to this variety, the handling and processing of dermatological specimens pose unique challenges. The small size, disparate shapes, and anatomic variation seen on skin biopsies require specialized techniques to enable sufficient sampling, proper orientation, and accurate diagnoses. This chapter addresses issues related specifically to the processing of small specimens, evaluation for biopsies for alopecia, nail specimens, frozen sections, and specimens requiring direct immunofluorescence.

Morphopathological aspects of healthy nails and nails affected by onychomycosis

Patients of onychomycosis are common in the dermatology practice. Contemporary morphology creates opportunities to study the functional units of the nail when such infections occur from morphopathological point of view. There were 22 nails biopsies from onychomycosis patients taken for the research of morphopathological changes in the thickened nail plate affected by onychomycosis. Samples of cadaverous' nails were used as a control material. The material was stained with haematoxylin and eosin and immunohistochemical methods. Terminal deoxynucleotidyl transferase dUTP nick end labelling reaction and periodic acid-Schiff reaction were also performed. We found patchy hypertrophy in the granulose layer of the epidermis, with focal acanthosis. In the horn layer, we identified nests of parakeratosis of various sizes, with incorporations of homogenous and eosinophil masses. We found high levels of interleukin 6 and interleukin 10 positive cells in the nail bed and in the bloodstream. Interleukin 1, however, was not a part of any of the functional units of any of the nails. Significant amount of fibres containing human beta defensin-2 were found in the bed and plate of the nail. Therefore one can conclude that as regards the nails affected by onychomycosis, the most effective morphopathogenical processes include cytokine and defensin excretion occurrence in the nail bed.