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BACKGROUND Dermatologists specialize in treating conditions of the skin, hair, and nails; however, it is our experience that the field of nail diseases is the least discussed facet of dermatology. Even less acknowledged is the complexity of nail procedures and how best to accurately code for these procedures. OBJECTIVE To convene a panel of experts in nail disease to reach consensus on the most accurate and appropriate Current Procedural Terminology (CPT) codes associated with the most commonly performed nail procedures. METHODS A questionnaire including 9 of the most commonly performed nail procedures and potential CPT codes was sent to experts in the treatment of nail disease, defined as those clinicians running a nail subspecialty clinic and performing nail procedures with regularity. A conference call was convened to discuss survey results. RESULTS Unanimous consensus was reached on the appropriate CPT codes associated with all discussed procedures. LIMITATIONS Although this article details the most commonly performed nail procedures, many were excluded and billing for these procedures continues to be largely subjective. This article is meant to serve as a guide for clinicians but should not be impervious to interpretation in specific clinical situations. CONCLUSION Billing of nail procedures remains a practice gap within our field. The authors hope that the expert consensus on the most appropriate CPT codes associated with commonly performed nail procedures will aid clinicians as they diagnose and treat disorders of the nail unit and encourage accurate and complete billing practices.

Background Psoriasis is a chronic inflammatory skin disease in which lesions display angiogenesis and increased vascularity. Objective The long-pulsed 1,064-nm neodymium:yttrium-aluminum-garnet (Nd:YAG) laser treats vascular lesions which suggests that it might also be used to treat nail psoriasis. Methods Sixteen patients (10 males and 6 females) with isolated nail psoriasis or nail with only mild cutaneous involvement were enrolled in the study. Nails were treated for 3 sessions with long-pulsed 1,064-nm Nd:YAG laser once monthly. During the course of the treatment, nail bed and matrix Nail Psoriasis Severity Index (NAPSI) scores were recorded. Results The mean baseline NAPSI score was 26 ± 7.2. The means of total NAPSI scores after the first, second, and third treatment sessions were as follows: 22 ± 6.6, 13 ± 6, and 5.7 ± 4.3, respectively. The decline in NAPSI score was statistically significant. At the end of the 3 treatment sessions, both nail bed and matrix lesions significantly responded to Nd:YAG laser treatment. Conclusion The Nd:YAG laser is a promising treatment option for nail psoriasis.

Pincer nail deformity (PND) is characterized by an excessive transverse curvature of the nail plate that increases along the longitudinal axis of the nail. Although many conservative and surgical techniques have been used in clinical practice, an established consensus for the correction of PND has not been present yet.Aim of the technique described in this article is to provide to restore the suitable nail-matrix system curvature by a simplified and quick approach, which could be seen as a synthesis of conservative and surgical treatments described in the literature.Nineteen cases of pincer nail of the great toe in 14 patients were analyzed. After softening nail plate with 5% thioglycolic acid solution for at least half an hour, surgical bilateral matricectomy and 2 anticonvex sutures with 1-0 polypropylene were performed to ensure proper nail plate shape. Besides demographic data, visual analog scale (VAS) score for pain, width index, height index, patient and surgeon satisfaction scores, operation time, and the day of painless return to the daily activities were investigated.A statistical significance was observed in VAS score for pain, width, and height indices between preoperative and postoperative values.This report gives acceptable outcomes with a combination of surgery and conservative treatments.

Nail clipping specimens are commonly submitted for the microscopic evaluation of nail disease; however, there may be missing clinical history regarding nail polish or other adornments present on the nail at the time of specimen retrieval. For this study, 6 types of nail cosmetics were chosen and applied to the nail plate of a volunteer. After a period of at least 24 hours, the nail plates with adornments and a control nail plate were clipped and placed in formalin. Specimens were processed using a standard nail protocol. All of the specimens, except the sticker appliqué, survived the fixation process. The glitter nail polish was the only specimen found to be polarizable. None of the specimens that survived fixation were found to be PAS-positive. Cosmetic nail enhancements are easily differentiated from the nail plate microscopically; nail cosmetics appear as a distinct layer of inorganic material lying atop the nail plate. There were 2 main microscopic patterns noted on the specimens: those with 2 layers and those with 3 layers.

BACKGROUND Racial melanonychia striata is a nail plate dyschromia described as a gray coloration of the background in dermatoscopy and hypermelanosis in histology. However, many cases with brown or black coloration of the background in the dermatoscopic examination have been followed. OBJECTIVE Evaluate racial melanonychia striata dermatoscopical patterns and histological diagnosis in Fitzpatrick skin Types IV, V, or VI population. MATERIALS AND METHODS 482 Fitzpatrick skin Types IV, V, or VI patients, between 19 and 72 years of age, were clinically evaluated and underwent nail plate dermatoscopic examination. Fifty-eight patients presenting melanonychia striata and dermatoscopic patterns with brown or black coloration of the background were submitted to a nail matrix biopsy. When occurring in more than 1 digit, biopsy was performed in the lesion with the darkest coloration presented in dermatoscopy. RESULTS All skin Types IV, V, or VI patients who had melanonychia striata, with brown or black coloration of the background in the dermatoscopic examination, revealed histopathological analysis compatible with hypermelanosis. CONCLUSION Racial melanonychia in skin Types IV, V, or VI patients, resulting from hypermelanosis, may present brown or black coloration of the background in the dermatoscopic examination.

A subset of patients with melanoma present in rare and unique clinical circumstances requiring specific considerations with respect to diagnostic and therapeutic interventions. Herein we present our review of patients with: (1) primary mucosal melanoma of the head and neck, gastrointestinal and genitourinary tracts; (2) primary melanoma of the eye; (3) desmoplastic melanoma; (4) subungual melanoma; (5) melanoma in special populations: children, non-Caucasians, as well as a discussion of familial melanoma.

We have recently described a new nail tumor known as onychocytic matricoma. Herein, we describe its malignant counterpart. Clinically, the tumor simulates onychomatricoma (OM). Histologically, this in situ malignant epithelial tumor exhibits a distinct picture of onychocytic differentiation with signs of both nail matrical differentiation and nail plate differentiation. We have proposed the name onychocytic carcinoma for this singular adnexal neoplasm. Given the peculiar thickening of the nail plate observed in OM, onychocytic matricoma, and onychocytic carcinoma, the clinical individualization of a new type of nail band pattern could be proposed. It presents as an acquired localized (monodactylous) longitudinal pachyonychia. Such longitudinal pachyonychia allow the recognition of the matrical nail tumor, which has a limited etiological spectrum. Xantholeucopachyonychia suggests mainly OM and rarely onychocytic carcinoma. Pachymelanonychia suggests onychocytic matricoma and rarely pigmented OM or onychocytic carcinoma.

Background Nail fold deformities from burn injury frequently result in eponychial retraction, proximal nail exposure, pain, and distal phalangeal function impairment. Secondary nail abnormalities including longitudinal ridges, surface cracks, and fragility are common sequelae to nail fold deformities. Surgical management of postburn nail fold deformity is challenging because of scar contractures involving the dorsum of digits and lack of surrounding healthy tissues that can be used as source of soft tissue for reconstruction. Previous reports have discussed several methods for reconstruction of these deformities. However, all of these methods are associated with significant donor site morbidities. Methods From August 2008 to January 2010, "onion" flap reconstruction was performed for postburn nail fold contractures and deformities on 32 fingers of eight patients (five men and three women; average age, 44.4 years; age range, 23-54 years). This novel technique was used to release scar contractures in the eponychial area and allow soft tissue restoration by redraping the eponychium in a single-step procedure. All 32 fingers received single-stage "onion" flap reconstruction for their nail fold deformities at least 6 months after the initial injury. Results The follow-up period, with an average of 7.8 months, revealed that all nails had good esthetic and functional results. All experienced amelioration of nail abnormalities. The "onion" advancement flap had effectively released the scar contracture around the nail fold and simultaneously restored the eponychial fold. Conclusions The "onion" flap technique provides superior results compared with those from conventional techniques. We recommend it as the mainstay of treatment for reconstruction of the postburn eponychial deformities. Level of evidence V, therapeutic study.

Onychomatricoma (OM) is an uncommon benign tumor of the nail thought to exhibit differentiation limited toward the nail matrix. Four recent articles from our laboratory have shown, in some respect, a morphological and immunohistochemical homology between the nail unit and the hair follicle at the level of the matrix and isthmus. The purposes of this article are as follows: to investigate whether the sequential pattern of hair keratin expression in the normal nail matrix is maintained in OM, to compare and contrast follicular tumors with matrix differentiation in OM, and to furnish morphological and immunohistochemical markers of the onychogenic capacity of OM. Formalin-fixed paraffin sections from 6 OM were examined using specific keratin (K) antibodies for the matrix, nail bed, and nail isthmus. Hair keratins were expressed in a sequential pattern similar to normal nail matrix. In 3 cases where the cavities were completely lined by the fibroepithelial projections, the morphological aspect and the pattern of expression of K5, K17, K6, K16, and K75 suggested a differentiation toward the nail bed and the nail isthmus. This study shows for the first time that OM can recapitulate the entire nail unit with differentiation toward the nail bed and the nail isthmus. We have identified new histopathological and immunohistochemical features in OM, and we have abridged the diversity of its histological presentation in 2 main patterns: a lobulated or foliated pattern, observed principally on transverse section, and a "glove-finger" mono- or multidigitate pattern, observed mainly on longitudinal section. We have also concluded that OM is not a nail variant of trichoblastoma, pilomatricoma, or other pilar tumors. The concept of epithelial onychogenic tumor with onychogenic mesenchyme could shed more light about the true nature of this peculiar mixed tumor. However, the term OM is short and sanctioned by usage, which justifies keeping it.

The etiology of longitudinal melanonychia (LM) is difficult to establish by clinical and dermoscopic examinations alone. Microscopic examination of the nail matrix remains crucial. Two groups of LM may be identified: melanocytic activation (melanic pigmentation of the matrix epithelium without any increase in the density of melanocytes) and melanocytic proliferation (lentigo, nevus, or melanoma). The histological examination is challenging, and immunohistochemical investigations can be helpful. The objective of this study was to analyze the immunohistochemical findings with routinely used markers in melanocytic tumors-S-100 protein, HMB-45, and Melan-A-in LM. A series of 40 cases were analyzed: 10 activations, 4 lentigines, 7 nevi, 12 in situ melanomas, and 7 invasive melanomas. The sensitivity of S-100 protein is weak in benign and malignant intraepithelial melanocytes of the nail matrix, and if this marker is performed alone, it may be wrongly reassuring. However, the use of S-100 protein is essential to differentiate invasive melanoma, lacking an intraepithelial component, and particularly desmoplastic melanoma, from epithelial and mesenchymal tumors. HMB-45 and Melan-A are more sensitive than S-100 protein for the evaluation of intraepithelial melanocytic proliferation of the nail apparatus, with HMB-45 being the most intense marker. In the dermal component, HMB-45 and Melan-A were less sensitive than S-100 protein. In conclusion, we recommend that the panel of antibodies used for histological evaluation of LM should include HMB-45 and/or Melan-A and S-100 protein only if an invasive melanoma is suspected.

To further define the clinicopathological spectrum of onychomatricoma (OM). We report the clinical feature, histological, and immunophenotypic characteristics of 19 cases of OM diagnosed between 2002 and 2007. The characteristic histologic appearance of OM is sometimes difficult to grasp because of 3 main factors: the anatomic particularities of the nail apparatus, the often fragmented aspect of the tissue specimen, and the choice of the section planes, which strongly modified the morphologic appearances observed. To prevent these difficulties, we built a tridimensional model using serial, transverse, and longitudinal sections. This reconstitution gives us a better understanding of the apparent diversity of the morphologic aspects observed in linking them to the anatomic site of the tumor. OM of the matrix is characterized by a thick nail plate with porch roof. OM of the ventral aspect of the proximal nail fold (PNF) is characterized by a nail plate without porch roof, exhibiting either a woodworm-like appearance or multiple cavities. In this second category, the fibrous base becomes elongated in shape, taking the shape of the anatomic contour of the PNF. The stroma gives rise to numerous fibroepithelial digitations. This pattern is different from the classical OM visualized in longitudinal sections, which appears as a single and large fibroepithelial tumor, that is, the multiple distal epithelial digitations arranged along a transversal plane are not seen. In the PNF variant, the characteristic clinical signs of OM fail to appear. We individualize 3 misleading clinical variants: tumor with a verrucous surface that is located in the lateral nail fold, as a band pattern suggesting wart or Bowen disease; a total dystrophy of the nail unit mimicking a squamous cell carcinoma; and pseudofibrokeratoma type. In the OM located on the ventral matrix, 3 new specific histologic variants were noted: pleomorphic OM, OM with a predominantly collagenous stroma, and superficial acral fibromyxoma-;like OM. OM is a benign tumor with a broader morphologic spectrum than previously thought. When the nail plate is not available, the immunohistochemistry can aid diagnosis by highlighting the peculiar immunophenotyping of OM, which expresses CD34 but not CD99, epithelial membrane antigen, S-100 protein, actin, and desmin.

BACKGROUND Photodynamic therapy (PDT) with aminolevulinic acid (ALA) has been used to improve recalcitrant periungual warts, but most lesions achieved complete remission after more than four sessions, and some lesions did not respond to the method. In this pilot study, the potential for synergistic effects of the combination of ablative carbon dioxide (CO2) fractional laser and methyl 5-ALA (MAL)-PDT for the treatment of recalcitrant periungual warts was examined. MATERIALS AND METHODS Twelve Korean patients (8 women and 4 men aged 20–45, mean age 27.9) with a total of 40 periungual warts were enrolled in the present study. The lesions were treated using an ablative CO2 fractional laser. Immediately after each fractional treatment, MAL was applied on the periungual warts, and 3 hours later, such areas were illuminated with a red light at a dose of 50 J/cm2 for 15 minutes. RESULTS After a mean of 2.2 treatments per wart, a mean clearance of 100% was achieved in 36 (90%) warts. Two warts (5%) had 50% clearance, and two (5%) showed no response after three treatments. There were no recurrences of the warts that had achieved 100% clearance during the follow-up period of 6 months. Most of the treatments had no severe side effects during or after their administration. CONCLUSION A potential for enhanced clinical results when using combined ablative CO2 fractional laser and MAL-PDT for the treatment of periungual warts was shown in this pilot study.

BACKGROUND The glomus tumor, described as a painful subcutaneous nodule, commonly occurs in subungual regions and is accompanied by tenderness and temperature sensitivity. In treatment of subungual glomus tumor, surgical excision is known to be the only curative method. Under surgical approach, it is challenging to minimize postoperative nail deformity and to reduce tumor recurrence. OBJECTIVE To evaluate the efficacy and safety of surgical treatment of subungual glomus tumor using simple blunt dissection. MATERIALS AND METHODS Twenty-three patients diagnosed with subungual glomus tumor underwent surgical procedure using a dorsal transungual approach. A single linear incision was made above the tumor, and the exposed mass was meticulously dissected with the opposite end of a single-end probe, and the tumor "popped up." Recurrence of symptom, tumor recurrence, and local complication were evaluated through long-term follow-up. RESULTS After a mean follow-up period of 30 months, only one case recurred, and partial-thickness skin necrosis occurred around the tourniquet site. There was no postoperative nail deformity. CONCLUSIONS In treatment of subungual glomus tumor, meticulous simple blunt dissection using a transungual approach led the tumor to "pop up" from the tumor bed. This unique and simple method of treating subungual glomus tumor showed low recurrence and minimal complications.

Epidermodysplasia verruciformis (EV) is a rare autosomal-recessive condition associated with a predisposition to infection with specific types of human papillomaviruses. A spectrum of wart-like lesions on the face, dorsa of the hands, and legs are characteristic clinical findings. Lesions usually develop in early childhood, persist, and may eventuate in cutaneous squamous cell carcinoma, usually in sun-exposed areas. These lesions are locally destructive and sometimes metastasize. We present a case of a 34-year-old African American woman with EV with a 9-month history of a right index finger ungual longitudinal pigmented band and nail splitting. Biopsy showed hyperkeratotic and parakeratotic subungual epithelium with verrucous hyperplasia. The superficial keratinocytes showed koilocytic changes. In addition, there was extensive, focally full-thickness keratinocyte dysmaturation with variable nuclear atypia and numerous mitotic figures, without apparent invasion. An associated melanocytic hyperplasia (confirmed by Melan-A stain), composed of large, pigment-laden dendritic melanocytes, was present without appreciable atypia or pagetoid spread. The findings are of a squamous cell carcinoma in situ arising in association with EV with incidental melanocytic hyperplasia. To the best of our knowledge, this is first report of a subungual presentation of this condition with associated melanonychia.

The distinction between a benign subungual pigmented macule (lentigo) and an early lesion of melanoma in situ can be difficult. To identify histologic parameters of potential diagnostic value, we retrospectively reviewed biopsies and excisions of 35 pigmented nail lesions. We studied 20 melanomas (10 invasive and 10 noninvasive) and 15 benign subungual melanotic lentigines. Ten specimens of normal nail apparatus obtained for reasons other than melanonychia were also examined as controls. The parameters, which were analyzed, included the density of melanocytes, the presence of multinucleated cells, pagetoid spread, cytologic atypia, inflammation, and the distribution of melanin pigment. The density of melanocytes was measured as the number of cells per 1 mm stretch of subungual dermo-epithelial junction [=melanocyte count (MC)]. The MC for invasive melanomas was as follows: mean=102, median=92.5, and range 52 to 212. For noninvasive (only in situ) melanoma, the mean MC was 58.9, median 51, and range 39 to 136. For benign subungual melanotic macules, the mean MC was 15.3, median 14, and range 5 to 31. In normal controls, the mean MC was 7.7, median 7.5, and range 4 to 9. Qualitative features associated with in situ melanoma and useful for its distinction from benign subungual melanotic macules included the presence of confluent stretches of solitary units of melanocytes, multinucleated melanocytes, lichenoid inflammatory reaction, and florid pagetoid spread of melanocytes.

BACKGROUND Digital myxoid cyst is relatively common on the digits. Nail changes and osteoarthritis are usually associated with this pathogenesis. OBJECTIVE The objective was to clarify this relationship and its significance by analyzing the clinical, radiologic, and pathologic data. METHODS AND MATERIALS Fifty-one patients with digital myxoid cysts were diagnosed and analyzed during a 5-year period. RESULTS Thirty-eight (74.5%) of 51 patients showed radiologic evidence of primary interphalangeal joint osteoarthritis in the affected digits. Among the 39 cysts removed surgically and examined pathologically, 28 were myxomatous and 11 were ganglion. Different clinical manifestations of nail change, including longitudinal grooves (20 cases), concave canaliform dystrophy (9 cases), "washboard" transverse lines (5 cases), and longitudinal grooves with beaded ridges (1 case) were found. CONCLUSION Osteoarthritis of the adjacent terminal joint is an important factor involved in forming digital myxoid cysts. Of the two cyst types, ganglion cysts are related to osteoarthritis more often than myxomatous cysts. Nail changes, secondary to matrix damage, are reliable clinical signs of underlying cyst formation. Understanding the pathogenesis of the digital myxoid cyst in relation to osteoarthritis and nail deformity helps inform the care of these patients.

Skin and/or pulmonary involvement occur frequently in Langerhans cell histiocytosis (LCH) whereas nail involvement is rare. Herein, we present a case of LCH with initial nail disease and subsequent lung involvement causing recurrent pneumothoraces. Systemic chemotherapy was applied and intrapleural bleomycine and thoracoscopic pleurodesis with talc were performed. Although prognosis is not satisfactory in LCH with recurrent pneumothorax and nail involvement, the patient is under follow-up with no evidence of skin lesions, nail involvement, and pneumothorax for the last 10 months.

Background Ingrown toenail is a common nail disease that causes pain, discomfort, and difficulty in walking. It is treated with either conservative therapy or surgery. Objective To present a new surgical approach to ingrown toenail. Materials and Methods For 19 ingrown toenail borders of 14 toes in 14 patients (1 male and 13 females), the nail matrix was stained with methylene blue and then partial matricectomy was performed with a CO2 laser. Results There was no recurrence at 18 nail borders after a mean follow-up period of 13.4 months, whereas a spike grew at one border but caused no walking pain. No serious complications occurred. Cosmetic improvement was also satisfactory. Conclusions Partial nail matricectomy with a CO2 laser after staining the nail matrix with methylene blue allows visual confirmation of the completeness of cauterization. TOSHIYUKI OZAWA, MD, KENSUKE NOSE, MD, TERUICHI HARADA, MD, MICHINARI MURAOKA, MD, AND MASAMITSU ISHII, MD, HAVE INDICATED NO SIGNIFICANT INTEREST WITH COMMERCIAL SUPPORTERS.

Background. Cutaneous metastases are variable in location and morphology. Metastatic tumor can present as a subungual lesion in either an oncology patient or a previously cancer-free individual. However, the diagnosis of a subungual metastasis is often not initially considered since the symptoms and appearance of the subungual tumor frequently mimic those of other conditions. Objective. To describe the clinical characteristics, radiographic changes, and pathologic findings of the subungual metastases in two women with metastatic carcinoma and to discuss the features of metastatic tumor lesions to the subungual area and distal digits previously reported in oncology patients. Methods. The clinical presentation, radiologic studies, and pathologic examination of metastatic subungual tumor lesions were described in two oncology patients: a woman with breast cancer and a woman with renal cell carcinoma. The published reports of cancer patients with subungual metastases were reviewed and the following variables were evaluated: the primary origin of the cancer, the histology of the primary tumor, the temporal relationship between the onset of symptoms or the appearance of subungual metastasis and the diagnosis of the visceral malignancy, the symptoms and the morphology of the subungual metastases, the clinical differential diagnosis of subungual metastases, the relationship between the site of origin of the primary tumor and the incidence of metastases either to the fingers and the thumbs or to the toes, the distribution of subungual metastases, the incidence of radiologically confirmable bony involvement of the distal phalanx by metastatic tumor in the digit containing the subungual metastasis, and the prognosis of patients in whom the diagnosis of a subungual metastasis has been confirmed. Results. Subungual metastases most frequently occur in patients with primary tumors of the lung (41%), genitourinary tract organs (17%, of which the kidney represents 11%), and breast (9%). The histology of the primary tumors that was most common included renal cell carcinoma and squamous cell carcinoma. The appearance of the subungual tumor was the first sign of a previously unsuspected primary malignancy in 44% of the patients with subungual metastases. Subungual metastases were frequently painful and most often presented as either an erythematous enlargement or swelling of the distal digit or a red to violacious nodule that distorted either the nail plate or the soft tissue of the distal digit, or both. The lesion was often initially mistaken as an acute infection. The lesion involved one or more digits of the hands in 92% of patients with subungual metastases; symmetrical subungual metastases and metastatic tumor restricted only to the great toes were less commonly observed. In patients with subungual metastases that involved the digits of their hands, the most frequent sites of primary tumor origin were the lung (35%) and the genitourinary tract organs (25%). Radiologic evidence of bony involvement of the respective distal digit was either initially present or subsequently developed in 92% of patients with subungual metastases. Patients with subungual metastases have a poor prognosis; their survival following the diagnosis of the subungual tumor is usually only a few months. Conclusion. The clinical differential diagnosis of a new periungual or subungual lesion (with or without an associated nail plate dystrophy) should include tumor metastasis to the nail unit not only in oncology patients, but also in previously cancer-free individuals.

The growth of the nail is primarily from the nail bed and mostly from the germinal matrix component, and to some extent from the sterile matrix as well. The purpose of this article is to describe the approach and technique of a composite nail, nail bed, hyponychium, and perionychium transplant when the total nail and nail bed need reconstruction. A case is presented when a nail bed junctional nevus is excised and reconstruction with nail unit matrix transplantation and the result is shown.

Nail biopsy is a safe and useful diagnostic procedure for many nail disorders when routine clinical and laboratory methods fail to produce a diagnosis. Prerequisites for nail biopsy are an understanding of the surgical anatomy of the nail, adequate anesthesia and hemostasis, and a nail abnormality for which histopathology can provide the diagnosis. Indications and methods for nail biopsy vary according to the site and type of pathology in the nail unit. Nail bed and perionychial biopsies can be performed easily and with minimal scarring. They are most commonly used to diagnose tumors as well as infectious and inflammatory disorders of the nail. The most important reason to biopsy the nail matrix is to make or exclude the diagnosis of melanoma in a patient with longitudinal melanonychia. Great care must be taken in nail matrix biopsy to minimize the risk of permanent nail dystrophy.

Background. The realm of nail unit surgery encompasses the dermatologist as well as the hand surgeon. Nail surgery complications may include allergy to anesthetic, infection, hematoma, nail deformity, and persistent pain and swelling. Objective. To review the pertinent literature regarding nail unit surgery complications. Methods. A Medline literature search was performed for relevant publications. Results. Nail unit surgery complications appear to be relatively infrequent. The majority of postoperative nail deformity complications result from nail matrix damage. Conclusion. Complications may be reduced to a minimum by preventive measures, such as careful patient selection, sterile technique, and gentle treatment of the nail matrix.

The anatomic singularities of the nail unit explain why bony tumors and osseous outgrowths of the distal phalanx quickly interfere with the nail apparatus. Osteochondromas (or exostosis) are benign osteocartilaginous outgrowths most commonly located on the hallux. They are by far the most common bony lesions affecting the nail unit. While frequently considered benign tumors, subungual exostoses are better regarded as reactional osseous outgrowths rather than true tumors. Enchondromas (better named chondromas) are intraosseous tumors whose location at the distal phalanx is rare. Large tumors may be responsible for phalanx deformity.

The nail unit can be a challenging anatomic location for surgical removal of neoplasms. Although uncommon, malignancies do affect this specialized epithelial structure. In particular, Bowen's disease and more invasive squamous cell carcinoma (SCC) are the most common neoplasm's to affect the nail unit and surrounding structures. Other neoplasm's such as basal cell carcinoma and malignant melanoma can also affect the nail unit, but less frequently, and will not be discussed in the scope of this review. Mohs micrographic surgery continues to be the treatment of choice because of the procedure's tissue-sparing qualities. A clear understanding of the anatomy and the histology of the nail unit, a review of the technique of Moh's surgery of the nail anatomy, as well as a review of the literature are presented.

Background. Warts are the most common nail tumor and mostly affect children and young adults. Periungual warts are usually due to HPV-1, 2, and 4. Development of periungual warts is favored by maceration and trauma, especially nail biting. Objective. To discuss the biology, clinical features, and medical and surgical treatment of periungual warts. Methods. Review of the literature and personal experience. Results. The natural course of warts makes aggressive approaches restricted to selected cases. Medical treatments, usually topical, include keratolytic agents, virucidal agents, and immunomodulators. All choices have been utilized successfully, but keratolytic agents are the best first-line approach. Surgical treatments include cryotherapy, surgical excision, electrosurgery, infrared coagulation, localized heating with a radio-frequency heat generator and laser therapy, especially the Er:YAG laser, which has an excellent safety profile. Conclusions. Definitive cure is not guaranteed by any therapy and periungual warts can recur and become larger after correct treatment.

Subungual exostosis is a benign osteochondral tumor usually involving the distal phalanx of the great toe. The lesion most frequently occurs in the second and third decades of life and is rare before the age of 10 years. There are few reports of its occurrence in children, and most of them advocate partial or complete nail excision to treat this lesion successfully. We report our experience with six children and adolescents using a simple surgical technique that involves approaching the exostosis under the nail to preserve nail coverage. Rapid recovery and excellent cosmetic appearance were achieved immediately after the operation.

Stubbing injuries to the great toe can be a cause of occult open fractures and osteomyelitis. Five such patients were identified after conducting a retrospective review of injuries to the hallux between January 1998 and December 1998. The study was conducted to draw attention to the association between this trivial trauma and its possible complications. All five children had open fractures of the distal phalanx of the great toe. Osteomyelitis did not develop in the children whose injuries were recognized early and who were treated with antibiotics. However, three children with delayed diagnoses and treatment developed osteomyelitis. At a mean follow-up of 10 months (range, 9-11) after injury, all five fractures had healed with no active signs of infection. Two of these children experienced a partial growth arrest and two experienced a full growth arrest of the distal phalanx of the great toe, the significance of which is yet unknown. Clinical signs such as bleeding from the eponychium and a laceration proximal to the nail bed should alert physicians to the presence of a possible open fracture. Early detection and treatment of these injuries may reduce or eliminate hospital stays and prolonged intravenous antibiotic treatment for osteomyelitis.

From 1970 to 1996, 93 patients received diagnoses of subungual melanoma. Followup data were complete on all patients and reviewed with a median duration of followup of 5.2 years. This study identifies significant clinicopathologic variables that affect survival and provides the orthopaedic surgeon assistance in the early diagnosis and treatment of this lesion. Eight-three percent of patients presented with Stage I disease, whereas 17% had nodal or distant disease. Fifty-three percent had locally advanced disease at presentation. Twelve percent of the patients were African-American. Fifty-five percent of the lesions arose on the hands with thumb involvement predominating in more than half of these cases. Operative therapy consisted of amputation. Elective lymph node dissection was performed in 34 patients (37%) for Stage I tumors of intermediate thickness. Therapeutic node dissection was required in 16 patients (17%) for positive nodes. Five-year survival was 74% for patients with Stage I disease and 40% for patients with Stage II disease. Statistical analysis identified stage at diagnosis, Clark and Wihm's level, the patient's race, and the presence of ulceration as prognostic variables affecting survival. The diagnosis of subungual melanoma carries a grave prognosis and often is misdiagnosed in the early stages. The treatment of choice is amputation at the appropriate level.

Pincer-nail syndrome has been described as distortion in the shape of the nails with excessive transverse curvature of the plate that increases from proximal to distal, leading to pinching and loss of soft tissue in the affected digit, resulting in severe pain. Many treatments have been recommended, but an effective long-term method that preserves the nail matrix has not been described. A method of dermal grafting under the nail matrix is described, and the results of treatment of six digits are reported. Five women and one man with an average age of 52 were treated. The affected digit was the thumb in four patients and the great toe in two patients. Follow-up averaged 25 1/2 months. The results were good in all cases with only one side of one nail remaining slightly curved. Pain was relieved in all cases, and complete adherence of the new nail plate occurred. Dermal grafting seems to provide excellent long-term treatment of the pincer-nail deformity with preservation of the nail matrix.

Pigmented lesions of the nail bed, especially without a history of trauma, represent a diagnostic challenge to the clinician. These lesions are often categorized as melanonychia striata (MS), which refers to any linear tan-brown-black pigmentation of the nail bed. The differential diagnosis of MS includes subungual hematomas, onchomycosis nigricans, junctional nevi, melanoma in situ (MIS), and malignant melanoma (MM). Our algorithm at the New York University (NYU) Medical Center for the treatment of pigmented lesions of the nail bed is presented. A histopathologic diagnosis with any evidence of melanocytic atypia, however subtle, requires absolute confirmation by complete excision. The absence of a clear margin or recurrence requires total nail bed excision and reconstruction using a full-thickness graft. The diagnosis of MIS is similarly treated. The surgical management of subungual MM is discussed. All cases of MM of the hand treated at NYU were reviewed. In all, 30 patients were treated from 1982 to 1995. Follow-up ranged from 6 months to 13 years. In our series, there were 8 cutaneous and 22 subungual melanomas. There was a marked delay in treatment of both groups, with subungual melanomas more often erroneously treated as other pathology prior to correct diagnosis. The 5-year survival rate was 100% for patients with cutaneous lesions, but only 80% for those with the subungual variety. There was a statistical difference in the depths of the lesions (subungual, 3.68 mm; cutaneous, 1.36 mm) with a p-value of 0.008. The role of elective lymph node dissection in the absence of clinical metastases as well as intraoperative sentinel lymphatic mapping remains controversial and is discussed.

A new osseointegrated anchorage device that holds a prosthetic nail plate was used successfully in eight patients, for a total of nine missing fingernails, secondary to trauma. There was only one early failure associated with patient noncompliance. The average follow-up time was 18 months. Details of the technique and three illustrative cases are presented.

Background. The most commonly used treatment method for subungual hematoma is nail trephining, which has some disadvantages. Objective. To introduce a very simple and well-tolerated treatment technique for this common problem. Methods. We used an extra-fine, 29-gauge insulin syringe for evacuation. We inserted the needle very close to the nail plate to minimize pain. We drained the blood from the hyponychium under the nail plate using this extra-fine needle. Results. The technique described herein is very fast and simple, and the patients tolerate it well. It is particularly successful for the treatment of smaller subungual hematomas of the second, third, and fourth toenails, in which the trephining is harder. Conclusion. For these reasons, we suggest this technique as a practical alternative to the traditional nail trephining methods.

Background. Squamous cell carcinoma (SCC) of the nail unit is a rare but often underappreciated neoplasm. Treatment can be delayed due to confusion with paronychia and verruca. Infection with human papilloma virus (HPV) has been associated with this malignancy. Objective. To describe the development of a superficially invasive SCC of the proximal nail fold in a patient infected with HIV, to report the association of a previously unrecognized HPV genotype, and to review key etiologic, diagnostic, and therapeutic points as related to SCC of the proximal nail fold. Results. This is the first report of HPV 26 coinfection in monogamous sexual partners, both of whom are HIV infected and have demonstrated lesions of malignant degeneration consistent with SCC. Conclusion. SCC must be considered in the differential diagnosis of nail fold neoplasm. An immunocompromised condition such as HIV/AIDS may predispose to malignant degeneration of lesions caused by infection with HPV.

Background A case of subungual squamous cell carcinoma, which is a rare malignancy and has an elusive etiology, is reported. Objective To present radiation therapy as a viable treatment option to amputation for surgically unresectable subungual squamous cell cancer. Methods A 69-year-old man with a 16-year-old history of subungual squamous cell carcinoma of the left thumb was treated by external beam radiation therapy. In this case, bone invasion precluded the patient from successfully completing Moh's micrographic surgery. Results The treated thumb at 17 months after radiation therapy remained tumor free. Conclusion Radiation therapy should be considered a treatment option for nail bed squamous cell carcinoma before considering amputation and perhaps as salvage for all unresectable lesions.

Nail pathology shares some common features with skin pathology, but it also has its own peculiar aspects. The anatomical and physiological characteristics of the nail unit probably play a major role in determining these pathological differences. Although the presence of keratohyaline granules is a normal feature of the skin, there is no granular layer in the normal nail matrix. As a consequence, nail matrix hypergranulosis should be considered a separate entity from skin hypergranulosis. In our review of 150 longitudinal nail biopsy specimens, keratohyaline granules were seen in the nail matrix of 24 cases of lichen planus, 29 cases of spongiotic trachyonychia, 10 cases of psoriasis, and three cases of Hallopeau acrodermatitis. In all cases, the presence of keratohyaline granules was associated with the absence of the normal keratogenous zone. Similar nail matrix features were detectable in three cases of malignant melanoma, two cases of primary systemic amyloidosis, and one case of histiocytoid hemangioma compressing the nail matrix. Our data suggest that inflammatory and compressive insults to the nail matrix cause both disappearance of the keratogenous zone and matrix keratinization with the formation of keratohyaline granules. Skin hypergranulosis reflects a hyperplasia of a normal skin component. In the nail matrix, however, hypergranulosis represents the appearance of structures not normally present. Nail matrix hypergranulosis should be considered a pattern of nail matrix reaction to different inflammatory insults. It is therefore more analogous to epidermal parakeratosis than to epidermal hypergranulosis.