Dermoscopy: What is your diagnosis?

The patient

A 36-year-old female with no previous history of melanoma presented for a routine mole check. A small, slightly raised lesion was discovered on the left side of her back (Figures 1, 2). What is your provisional diagnosis?

Figure 1.

Small, raised shiny lesion about 4 × 3 mm on the left flank of a 36-year-old woman. [Copyright: ©2013 Narayanan et al.]

Figure 2.

Dermoscopy of the lesion taken with Dermlite DL3. [Copyright: ©2013 Narayanan et al.]

Please send your answer to dpc@derm101.com. The first correct answer will receive a complimentary copy of the book, Dermoscopy: The Essentials, 2nd ed. [Elsevier-Saunders, 2012]. The case and the answer to the question will be presented in the next issue of Dermatology Practical and Conceptual.

July 2013 quiz—answer and discussion

The correct answer to the dermatoscopy quiz in the July 2013 issue is (http://dx.doi.org/10.5826/dpc.0303a07)

Molluscum contagiosum (MC) is a cutaneous infection caused by various types of the poxvirus, molluscum contagiosum virus (MCV)-1 to -4, with MCV-1 being the most common [1]. The virus is spread by direct skin-to-skin contact with lesions and typically occurs in young children, sexually active adolescent and adults, and immunosuppressed individuals. After viral entry, MCV replicates in the lower layers of the epidermis for an incubation period of 14 days to 6 months [2]. With active infection, the epidermis hypertrophies and extends into the dermis. Molluscum bodies begin to form within cells of the stratum spinosum, causing further enlargement of individual cells. The basal cell layer replaces the spinosa layer, projecting the hypertrophied spinosa cells towards the stratum corneum, forming the characteristic small (3 to 5 mm in diameter), smooth, pink-red, dome-shaped, umbilicated lesions [3]. The most commonly affected areas are the face, trunk, extremities, and genitals [1].

The diagnosis of MC is typically clinical. Unlike herpes viruses, MC is not routinely cultured. For challenging cases, the use of a dermatoscope may aid in diagnosis by allowing the clinician to visualize the characteristic white-yellow clods and surrounding vessels (molluscum bodies) [4,5]. Histopathology yields the final diagnosis in clinically unequivocal cases, demonstrating numerous characteristic inclusion bodies, which represent the molluscum bodies or Henderson-Paterson bodies [1]. In our case, the diagnosis was unequivocal and histopathology was not required.

Infection with MCV is self-limited and will usually resolve spontaneously within weeks to months, but patients are considered contagious until all MC lesions have disappeared. Therapeutic options for refractory lesions include topical tretinoin, topical cantharidin, surgical tape, light cryotherapy, topical trichloracetic acid, topical sodium nitrite with salicylic acid, or curettage [1]. We have also seen favorable results with topical cidofovir and ingenol mebutate.