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Dermatology Quiz and Case Discussion (4/14)

Hind Alshihry, MD
International Fellow, Pediatric Dermatology, Ann & Robert H. Lurie Children’s Hospital of Chicago
Disclosure: Dr. Alshihry has no industry relationships to disclose and does not refer to products that are still investigational or not labeled for the use in discussion.
Annette Wagner, MD
Attending Physician, Dermatology, Ann & Robert H. Lurie Children's Hospital of Chicago; Assistant Professor of Pediatrics and Dermatology, Northwestern University Feinberg School of Medicine
Disclosure: Dr. Wagner has no industry relationships to disclose and does not refer to products that are still investigational or not labeled for the use in discussion. Read Dr. Wagner's profile.
Dr. Mary Nevin, Course Director; Vita Lerman, Editor; Dr. John X. Thomas, Senior Associate Dean for Medical Education; Genevieve Napier, CME Director, Tara Scavelli and Jennifer Banys, CME Project Specialist have nothing to disclose.

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Educational objectives

At the conclusion of this activity, participants will be able to:

  • Recognize the disorder shown in the photograph
  • Describe the clinical features of this problem that aid in diagnosis
  • Discuss the appropriate management of this problem

Estimated time to complete: 0.5 hours
CME Credit: 0.5

CME credit

Credit statement

How to earn credits

  1. Login or sign up.
  2. Read the article.
  3. Correctly answer at least 70% of questions on the quiz and answer evaluation questions.

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A 2-year-old female presents for evaluation of this nail change (Figure 1).

 

No other nails are involved. The parents are unsure when they first noted the change. They are unaware of any preceding trauma. The amount of nail involved with the change is increasing over time. She is otherwise healthy and thriving. No other cutaneous lesions are present on complete examination. She does not have tenderness in the area. 

1. What is the most likely cause of this nail change?         

a) Trauma         

b) Benign birthmark         

c) Side effect of oral medication         

d) Potentially serious tumor 

2. What is the best clinical approach to this problem?         

a) Discontinue oral medication         

b) Reassurance with yearly follow-up         

c) Surgery         

d) Avulsion of the nail to release trapped blood 

Answers:  1d, 2c 

Discussion:

Pigmentation in nails can be diffuse or in a striated pattern. It can be caused by excess production of melanin (melanonychia) or by the deposition of various substances within the nail plate (chromonychia) or under the nail plate, such as hemosiderin from a traumatic hematoma.

When brown/black discoloration occurs in multiple nails and is diffuse, systemic diseases should be considered, such as Addison disease, hyperthyroidism, hemochromatosis, Cushing disease or vitamin B12 deficiency.

When multiple nails are affected with striated of linear bands of brown or black pigmentation (melanonychia stiata), medications can be a source of dyspigmentation, including tetracyclines, antimalarial agents, and zidovudine. Removal of the offending agent does not guarantee that the nail discoloration will completely resolve but is recommended when possible.

Multiple pigmentary nail bands are also seen in some congenital syndromes, including Peutz-Jegher syndrome (hereditary intestinal polyposis syndrome: GI polyps, GI cancer risk, pigmented lesions of the oral mucosa, especially the lower lip, hands and feet including nails) and Laugier-Hunziker syndrome (benign hyperpigmented macules of the lips, buccal mucosa and genitalia with longitudinal melanonychia but no malignant associations).

The differential diagnosis of a solitary nail with a longitudinal brown or black pigmentary band in the nail plate includes hemorrhage under the nail from trauma, nail infection and melanonychia. Melanonychia refers to the deposition of melanin within the nail plate, which can be acquired or congenital, benign or malignant.

The most common cause of acquired single nail longitudinal pigmentation in children is a collection of blood under the nail from trauma or a nail hematoma. It is common for this to occur in a single nail, to be associated with trauma, although a negative history of trauma is common especially in younger children, and for the pigment to persist for many months. Tenderness may be noted at the onset but rarely persists. The change can be noted in a smaller area at first and expand over time, especially if the injury results in a significant blood collection.

The diagnosis of a nail plate hematoma can be difficult since the subungal change is often black and frequently mistaken for melanonychia. Magnification with a dermatoscope or even a hand held ophthalmoscope or otoscope can be helpful because the golden brown nature of the trapped hemosiderin can often be appreciated with magnification. If the injury is acute and associated with tenderness, avulsing the nail is rarely done to relieve discomfort or to confirm the diagnosis. More typically, the change slowly “grows out” with the nail plate growth over time, leaving minimal or no nail dystrophy. If trauma is significant to the nail matrix itself – the matrix or growing portion of the nail is under the cutlicle – nail plate dystrophy can occur and persist even as the color of the nail becomes normal over time.

Pigmentary change in nails can also be seen in a single nail with a subungal nail infection. Pseudomonas is a common organism to produce single nail infection, especially following nail trauma that produces onycholysis (lifting of the nail plate from the nail bed). Typical nail infection with Pseudomonas produces a dark green/black discoloration.

Melanocytic nevi that involve the nail plate or nail bed produce acquired solitary longitudinal brown/black pigmentary bands in the nail or melanonychia striata. These are uncommon in Caucasian patients but are found frequently in pigmented races. Congenital nevi involving the nail matrix can also occur but are even more uncommon. When acquired nevi develop in children, the pigment band slowly widens and darkens with time as the child grows.

The concern when a new solitary brown/black longitudinal band appears in the nail plate is malignant melanoma. One of the clinical signs that can be helpful to distinguish malignant melanoma or atypical nevi of the nail matrix from benign melanonychia striata is the presence of a Hutchinson’s sign. When benign nevi occur, the pigmentation does not exend onto the periungal nail folds or cuticle. Any extension of pigment onto the adjacent skin or cuticle is concerning for an atypical melanocytic tumor or melanoma, although exceptions do occur.

Another clinical pearl that is helpful in distinguishing benign acquired nevi that produce melanonychia striata from malignant melanoma is the clinical appearance of the longitudinal pigment band and the growth pattern. Acquired nevi in children develop beginning around 2 years of age. They start as small freckle-like hyperpigmented macules on the skin that enlarge and darken slowly with time. They are uniform in color, a single color and round or oval in shape with sharp demarcation. Children get a “matching set” of acquired nevi. All of the acquired lesions have a similar color and appearance. An atypical nevus in a child is most commonly the “ugly duckling” or nevus that looks different in shape or color from the other acquired moles. It can also be the nevus that grows more quickly. Any pigmented lesion (or dome shaped pink papule, since melanoma is more commonly amelanotic in children) that grows from the size of a freckle to a pencil eraser in 6 months is very concerning for melanoma. Spitz nevi have this growth pattern also in children and cannot be clinically distinguished from melanoma.

Similarly, the clinical appearance and growth pattern of an acquired nail matrix nevus can aid in the diagnosis. The lesion should appear after 2 years of age. It should have a well defined edge that starts out small and slowly expands over years. Like acquired nevi on the skin, the color should be uniform and match the color of acquired nevi elsewhere on the body. The color may darken with time and slowly widen, just as the color of normal acquired nevi darkens and widens. Any irregularity in shape, rapid growth or enlargement, or the presence of multiple colors within the band are concerning.

If the features of an acquired nail matrix nevus are benign, it is reasonable to follow the nevus over time observing for the changes described above. It is recommended that any child with melanonychia striata be evaluated and followed by a pediatric dermatologist. If at any time the longitudinal pigment band develops a Hutchinson’s sign, multiple colors or an ill-defined feathered edge, or undergoes growth that is more rapid than expected, the nevus should be surgically removed.

Surgical removal of the nevus is accomplished by complete or partial nail avulsion and removal of the involved area within the nail matrix and/or nail bed. This can be accomplished by a pediatric dermatologic surgeon, a hand or orthopedic surgeon or a pediatric plastic surgeon. It is recommended that a pediatric dermatologist evaluate the patient first before referral to surgery to ensure that only those nevi that are concerning for malignancy are removed. Removal or biopsy of a nail matrix nevus can result in severe nail dystrophy or complete loss of the nail plate. The nail plate is central to determining the shape of the distal digit in a growing child. No nail biopsy or excision should be performed unnecessarily in a child to prevent deformity of the nail and fingertip.

The patient in this vignette developed this area of longitudinal pigmentation before the age of 2 years when acquired nevi typically develop. The color of the pigment band was very black and darker than any of the freckle-like acquired nevi noted on physical exam. Significant and rapid growth of this area to a size larger than a pencil eraser was noted and a Hutchinson’s sign was present on the proximal cuticle. The nevus was fully excised with a complete nail matrixectomy to bone to prevent recurrence and with sacrifice of the entire nail plate. Pathology demonstrated a dysplastic junctional nevus with moderate atypia. No melanoma was identified. 

FOR FURTHER READING:

[1.] Goettmann-Bonvallot S, Andre J, Belaïch S. Longitudinal melanonychia in children: a clinical and histopathologic study of 40 cases. J Am Acad Dermatol 1999;41:17-22.

[2.] Leclère FM, Mordon S, Leroy M, et al. Presentation, microsurgical therapy, and clinical outcomes in three cases of expanding melanonychia of the nail unit in children. Arch Orthop Trauma Surg 2011 Oct;131(10):1453-1457.

[3.] Léaute-Labrèze Ch, Bioulac-Sage P, Taïeb A. Longitudinal melanonychia in children. A study of 8 cases. Arch Dermatol 1996;132:167-169.

[4.] Iorizzo M, Tosti A, Di Chiacchio N, et al. Nail melanoma in children: differential diagnosis and management. Dermatol Surg 2008;34:974-978.


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The Northwestern University Feinberg School of Medicine is accredited by the Accreditation Council for Continuing Medical Education (ACCME) to provide continuing medical education for physicians.

Credit Designation Statement

The Northwestern University Feinberg School of Medicine designates this enduring material for a maximum of 0.5 AMA PRA Category 1 Credit(s)™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.