DSU01902 © 2001 by the American Society for Dermatologic Surgery, Inc • Published by Blackwell Science, Inc ISSN 1076 0512/01/$15 00/0 • Dermatol Surg 2001;27 229–234 Nail Biopsy Indications and Metho[.]
Nail Biopsy: Indications and Methods Phoebe Rich, MD Oregon Health Sciences University, Portland, Oregon Nail biopsy is a safe and useful technique for diagnosis and management of many nail conditions A basic understanding of nail anatomy and biology is a prerequisite for a successful nail biopsy The patient must be adequately prepared and there needs to be excellent anesthesia and hemostasis The type of nail biopsy depends largely on the location of the pathology in the nail unit The techniques of nail biopsy by location in the nail unit and by lesion type are discussed THE NAIL BIOPSY is a useful technique for making a diagnosis of a clinically ambiguous nail condition that is not diagnosable by history, clinical appearance, and routine mycology It can be performed safely, painlessly, and with a minimum of scarring Nail biopsy can prevent serious outcomes in potentially harmful or disfiguring nail conditions The nail biopsy can be performed by a variety of techniques that are outlined in this article The objectives of a nail biopsy are to obtain a diagnosis of a nail condition in a safe technique without pain or permanent nail dystrophy.1 Prerequisites for a successful nail biopsy are the following: complete understanding of nail anatomy and biology, proper patient selection and preparation, adequate anesthesia and hemostasis, proper technique, and a nail condition that has eluded diagnosis by simple history, clinical inspection, and routine mycology (Table 1) The physician performing nail surgery needs a fundamental knowledge of nail unit anatomy, blood supply to the nail and hemostasis, sensory nerves, and anesthesia ible scar in the nail than a proximal nail matrix biopsy There is no subcutaneous tissue in the nail unit and the periostium lies immediately beneath the nail unit Therefore a biopsy of the nail is taken directly down to bone The insertion of the extensor tendon is approximately 12 mm proximal to the cuticle This structure is usually proximal in most nail surgeries (Figure 2) Anatomy of the Nail Unit A thorough understanding of the anatomy of the nail is crucial for a successful nail biopsy procedure The most vital structure in the nail unit is the nail matrix, which is visible as the half moon-shaped structure at the base of the nail The matrix is the germinative epithelium that produces nail plate (Figure 1).2 Damage to the matrix has the potential to permanently scar the nail It is useful to recognize that the distal matrix forms the inferior part of the nail plate and the proximal matrix forms the superficial layers of the nail plate A biopsy of the distal matrix is less likely to result in a visP Rich, MD has indicated no significant interest with commercial supporters Address correspondence and reprint requests to: Phoebe Rich, MD, 2222 NW Lovejoy St., Portland, OR 97210 Blood Supply and Hemostasis The lateral digital arteries are the main blood supply to the nail and course down the sides of the digit A tourniquet is rarely necessary to control bleeding in nail surgery, but when one is used, a flat Penrose drain or a digital tourniquet is helpful (Figure 3) If a tourniquet is used, it is important that it not be left in place for more than 15 minutes Hemostasis is easily achieved by applying pressure over the lateral digital arteries by gently applying pressure on the sides of the finger during the procedure Anesthesia Patient acceptance of nail surgery is sometimes hindered by worry about the pain of the procedure It is necessary to have perfect anesthesia and a painless procedure Cutaneous sensory nerves run parallel to the blood vessels down the sides of the digit Anesthesia can be applied in two locations: digital block and wing block (Figure 4) A digital block involves injection of up to cc of plain lidocaine into the lateral base of the digit A paronychial or wing block allows a smaller volume of anesthetic to be injected into the proximal nail fold and achieves more rapid anesthesia The small volume of anesthesia in the wing block causes blanching and facilitates hemostasis A well-prepared patient helps ensure a successful procedure A careful history and physical examination with a full differential diagnosis is an important starting point Use of medications such as coumadin and salicy- © 2001 by the American Society for Dermatologic Surgery, Inc • Published by Blackwell Science, Inc ISSN: 1076-0512/01/$15.00/0 • Dermatol Surg 2001;27:229–234 230 rich: nail biopsy Dermatol Surg 27:3:March 2001 Table Prerequisites for a Successful Nail Biopsy Understanding of nail anatomy and physiology Proper patient selection and preparation Adequate anesthesia Hemostasis A nail condition that has eluded diagnosis by routine clinical inspection, history, radiologic, and microbiologic techniques A dermatopathologist who is familiar with the histopathologic idiosyncrasies of the nail unit Figure Marmed digital tourniquet Figure The nail unit structures Figure Drawing of surgical anatomy of the nail unit lates and a medical history looking for diabetes, peripheral vascular disease, connective tissue disease, and prosthetic valves and joints are important Photographs are usually taken before the procedure The risk of permanent scarring and the possibility that a diagnosis will not be forthcoming even with an adequate biopsy should be discussed with the patient Imaging studies, primarily roentgenograms, are often an important prelude to the surgical procedure Table outlines the necessary routine preoperative preparation of the patient Instruments Proper instruments will make any nail biopsy easier Most of the instruments are standard skin surgery in- Figure Digital and wing block struments, however, there are a few specialized instruments (Figure 5) The Freer septum elevator (second from left, Figure 5) is a thin, curved instrument that has blunt blades on each end It is useful in avulsing the nail atraumatically and in protecting the matrix in nail fold biopsies (Figures and 7) Dermatol Surg 27:3:March 2001 rich: nail biopsy 231 Table Preoperative Examination of the Patient History Drugs: anticoagulants, allergies Heart valves, artificial joints Diabetes, PVD, connective tissue disease, arthritis, cutaneous disease Clinical examination All 20 nails Mucous membranes Skin and hair Laboratory X-ray Mycology, microbiology PAR Possibility of permanent dystrophy Possibility of no diagnosis Length of time for nail to regrow Bleeding, infection as with any surgery Photographs Types of Nail Apparatus Biopsies by Location The nail biopsy affords the clinician the opportunity to diagnose and treat nail disorders Nail biopsy is a safe and effective procedure when performed carefully and properly (Figure 6) The type of biopsy performed depends on two factors: the site of the pathology within the nail unit and the risk of permanent scarring from the procedure The most common techniques are excision, punch biopsy, and longitudinal nail biopsy When performing a punch biopsy excision in the nail unit, it is important to orient the excision properly for the best result (Figures 7–9) An excision in the nail bed is oriented longitudinally and a nail matrix excision is oriented horizontally A nail fold biopsy is similar to a biopsy elsewhere on the skin The nail biopsy techniques will be discussed by location in the nail unit Figure Poorly performed nail biopsy results in nail dystrophy agnostic and therapeutic The effect of a pathologic disorder on the nail bed results in several possible features: onycholysis, hyperkeratosis, dyschromia, erosion, and a mass that can distort the normal nail anatomy Nail bed biopsy is useful in distinguishing between several diagnoses that have similar clinical appearance (Table 3) Nail bed biopsy will often remove a lesion in its entirety Biopsy of the nail bed can be performed with a punch or by an elliptical excision The nail is usually avulsed prior to removing the specimen with a punch, although occasionally the punch can be taken through the nail plate using a larger punch for the plate and a smaller punch for the nail bed specimen An elliptical excision should be oriented in a longitudinal axis Defects larger than mm are usually sutured The nail bed heals without scarring, although there is occasionally some onycholysis Nail Bed Biopsy Nail bed biopsy is a simple technique that can be both di- Figure Instruments used in nail surgery The Freer elevator and the dual action nail nipper are on the left side Figure Diagram of site and orientation of nail biopsies 232 rich: nail biopsy Dermatol Surg 27:3:March 2001 Figure Lesion of the proximal nail fold Nail Fold Biopsy Figure A) Punch biopsy of the nail through the nail plate B) A punch biopsy of the nail matrix after nail avulsion It is safe and easy to perform a nail fold biopsy Indications are similar to a biopsy elsewhere on the skin A nail fold lesion can be removed with a shave, a punch, or an excision When the specimen is taken en bloc from the nail fold, a Freer elevator is inserted under the nail Table Nail Bed Disorders and Their Clinical Features for Which a Biopsy May Facilitate Diagnosis Diagnosis Malignant, premalignant, transitional tumors of the nail bed Squamous cell carcinoma, Bowen’s disease Basal cell carcinoma Melanoma Kaposi’s sarcoma Metastatic carcinomas Keratoacanthoma Benign tumors of the nail bed Enchondroma Glomus tumor Exostosis Osteochondroma Pyogenic granuloma Epidermal cyst Fibroma Infectious conditions of the nail bed Onychomycosis Warts Subungual (Norwegian) scabies Inflammatory dermatosis involving the nail bed Psoriasis Lichen planus Other nail bed conditions Hemorrhage, trauma Clinical Nail Findings Hyperkeratosis, dyschromia, onycholysis, destruction of nail plate Rare, variable clinical appearance Pigmentation of nail bed, erosion, destruction of nail plate, 25% amelanotic Pigmentation, elevation, destruction of the nail plate Mass, pseudo-clubbing, dystrophy, dusky red color, with or without pain Multiple or solitary, nail plate destruction, mass, erosion, granulation tissue, with or without pain Mass, alteration of nail plate, pain Spontaneous pain, blue red mass Mass, elevation of plate, tender, may see secondary infection Enlargement of digit, elevation or destruction of the nail plate Exuberant friable mass, needs to be distinguished from amelanotic melanoma Mass, nail plate deformity Mass, elevation, distortion of the nail Hyperkeratosis, dyschromia, dystrophy, onycholysis is negative Verrucous mass, sometimes painful, nail deformity, destruction, must distinguish from vericous carcinoma, squamous cell carcinoma Hyperkeratosis of hyponychium Onycholysis, hyperkeratosis, spliter hemorrhage, oil drop discoloration Violaceous discoloration, atrophy of nail bed; if nail matrix is involved, onychorrhexis, hapalonychia, pterygium Red/black discoloration under nail plate; persistent or nonmigrating hemorrhage needs to be distinguished from melanoma From P Rich Nail biopsy: indications and methods J Dermatol Surg Oncol 1992;18:673–82, with permission Dermatol Surg rich: nail biopsy 27:3:March 2001 233 is to confirm or exclude the diagnosis of malignant melanoma in a patient with a pigmented lesion of the nail (Table 4) The nail plate can be avulsed (partial proximal avulsion or total avulsion) or a punch biopsy can be taken through the nail plate An elliptical excision of the nail matrix should be oriented horizontally (transverse) and sutured for optimal cosmetic result Longitudinal Nail Excision Figure 10 En bloc excision of a nail fold tumor Note that the Freer elevator is inserted under the nail fold to prevent inadvertent damage of the matrix by the scalpel fold to protect the underlying matrix from inadvertent damage by the scalpel (Figures 10 and 11A) The nail fold heals beautifully by secondary intention Nail Matrix Biopsy The most important reason to biopsy the nail matrix For large lesions located in the lateral one-third of the nail, a longitudinal nail biopsy can be performed This technique samples all components of the nail unit including the nail matrix, nail bed, nail fold, and hyponychium and yields the best information (Figure 11) A discussion of nail matrix biopsies should include a specific reference to the treatment of pigmented bands in the nail and when and how those lesions should be addressed Longitudinal melanonychia (LM) and melanonychia striata are the terms used for pigmented bands in the nail plate that are caused by increased melanin content.3,4 Not all pigment in the nail is melanocytic; dematiaceous fungi and hemosiderin from blood under the nail are other causes of nail pigmentation (Table 5) There are no hard and fast rules when trying to Figure 11 Lateral longitudinal excisional biopsy A) Lateral longitudinal pigmented band in the nail B) Lateral excision from PNF to hyponychium along the lateral nail groove; medial incision through the PNF nail plate and nail bed to the hyponychium C) Dissection from periostium starting distally D) Dissection from periostium proceeding proximally E) Careful excision of the lateral matrix is important to prevent spicule formation F) The final defect G) Approximation of lateral nail fold by suturing through the nail bed and nail plate H) The specimen is oriented and diagramed for processing and interpretation I)Wound dressing for nail surgery: antibiotic ointment and a non adherent dressing J) A bulky gauze dressing protects the surgery site K) Lateral longitudinal biopsy: two weeks post surgery 234 rich: nail biopsy Dermatol Surg 27:3:March 2001 Table Indications for Nail Matrix Biopsy Solitary, unexplained pigmented band in Caucasians, to confirm or exclude the diagnosis of malignant melanoma Index of suspicion for malignancy may be raised by a band that is new, widened, very dark, present in an elderly patient, or located on the thumb, index finger, or great toe, or associated with pigmentation of the nail folds (Hutchinson’s sign); however, clinical evaluation alone may be inadequate to determine whether or not a longitudinal pigmented band is benign If there is any doubt, a biopsy is indicated Tumor involving the nail matrix Inflammatory dermatologic disorder presenting as a nail plate abnormality, indicating matrix involvement for example, lichen planus or psoriasis (The clinical application is primarily as a research tool.) From P Rich Nail Biopsy: indications and methods J Dermatol Surg Oncol 1992; 18:673–82, with permission decide whether a pigmented nail requires biopsy In a recent article, features that are helpful in making a clinical diagnosis of melanoma of the nail (abbreviated with the letters A–F) include age of the patient, brown/black and breadth less than mm, change in the band, digit involved, extension of pigment onto the nail folds (Hutchinson’s sign), and family history of melanoma and dysplastic nevi.5 These clinical guidelines are helpful, but the definitive diagnosis of a suspicious-looking pigmented band in the nail requires biopsy Although there are no definitive rules to follow, an algorithm written by Monica Lawry outlines a logical sequence that helps determine the necessity of a nail biopsy to rule out nail bed melanoma (Figure 12).6 There is a great deal of controversy about how longitudinal melanonychia in children should be approached Many authors believe that it is Table Some Nonmelanoma Causes of Pigment in the Nail Apparatus Melanin and melanin complexes Normal variant for skin phototype IV, V, and VIa Hypermealnonsis of the matrix epithelium (melanotic macule equivalent) Lentiginous melanocytic hyperplasiab Junctional nevusb Compound nevusb Bowen’s disease, squamous cell carcinoma, basal cell carcinomab Laugier–Hunziker syndrome, Peutz–Jegher syndromea Addison’s disease, Cushing syndromea Postinflammatory hyperpigmentation (i.e., lichen planus, trauma)c Drugs (AZT, antimetabolites, antimalarials, minocycline)a Heavy metal exposurea Nonmelanin pigmentation Dematiaceous fungic Bacteria (pseudomonas)c Hematoma (hemoglobin/hemosiderin)b a Most commonly seen in multiple digits b Most commonly seen in one digit c Can be seen in single or multiple digits Hemoglobin (may not be degraded to hemosiderin) stains with benzidine or Patent blue V From Lawry M, Rich P The nail apparatus: a guide for basic clinical science Curr Probl in Dermatol 1999;11:161–208, with permission Figure 12 Algorithm for the biopsy of pigmented bands in the nail Courtesy Monica Lawry, CP safe to follow pigmented nail lesions in children, although further long-term study may be warranted.7,8 Conclusion Nail biopsy is a useful technique that is safe when performed properly It facilitates the diagnosis of ambiguous, potentially serious nail conditions and can remove painful or disfiguring nail lesions Nail biopsies are well within the domain of all dermatologists and really not much more complicated than routine skin surgery When surgical anatomy of the nail is understood and careful techniques are followed, the success of the nail biopsy is assured Acknowledgment The figures in this article were reproduced from M Lawry and P Rich,6 with permission References Rich P Nail biopsy: indications and methods J Dermatol Surg Oncol 1992;18:673–82 Zaias N, Alvarez J The formation of the primate nail plate: an autoradiographic studying squirrel monkey J Invest Dermatol 1968;51: 120–36 Baran R, Kechijian P Longitudinal melanonychia (melanonychia striata): diagnosis and management J Am Acad Dermatol 1989;21: 1165–75 Dawber RPR, Colver GB The spectrum of malignant melanoma of the nail apparatus Semin Dermatol 1991;10:82–7 Levit EK, Kagen MH, Scher RK, Grossman M, Altman E The ABC rule for clinical detection of subungual melanoma J Am Acad Dermatol 2000;42(2 pt 1):269–74 Lawry M, Rich P The nail apparatus: a guide for basic and clinical science Curr Prob Dermatol 1999;11:161–208 Tosti A, Baran R, Piraccini BM, Cameli N, Alessandro P Nail matrix nevi: a clinical and histologic study of twenty-two patients J Am Acad Dermatol 1996;34:765–71 Leaute-Labreze C, Bioulac-Sage P, Taieb A Longitudinal melanonychia in children Arch Dermatol 1996;132:167–9 ... proximal nail fold Nail Fold Biopsy Figure A) Punch biopsy of the nail through the nail plate B) A punch biopsy of the nail matrix after nail avulsion It is safe and easy to perform a nail fold biopsy. .. one-third of the nail, a longitudinal nail biopsy can be performed This technique samples all components of the nail unit including the nail matrix, nail bed, nail fold, and hyponychium and yields... excision in the nail bed is oriented longitudinally and a nail matrix excision is oriented horizontally A nail fold biopsy is similar to a biopsy elsewhere on the skin The nail biopsy techniques