A 64-year-old man comes to the office with a 4-day history of severe left-sided chest discomfort. The pain is constant and has a burning quality. Over the last day, the patient has developed a rash in the area of discomfort. He has not had similar symptoms before. Past medical history is unremarkable. The patient is afebrile and vital signs are normal. Physical examination shows a vesicular rash at the 5th left intercostal space. Which of the following pathologic findings is most likely to be found in the affected area?
Varicella zoster virus (VZV) is an enveloped, double-stranded DNA virus transmitted via respiratory droplets or direct contact. Initial infection typically occurs in childhood and causes varicella (chicken pox), which is characterized by fever and a self-limited, diffuse vesicular rash. VZV then travels via sensory fibers to the dorsal root ganglia (or trigeminal ganglia), where it remains dormant for years. Weakening of cellular immunity leads to reactivation of the virus, which manifests as herpes zoster (shingles). Shingles is characterized by unilateral burning pain and a papular or vesicular rash in a dermatomal distribution. The lesions coalesce, rupture, crust over, and heal within a few weeks although the discomfort may linger for several weeks.
Light microscopy of a sample from a vesicle base reveals intranuclear inclusions in keratinocytes and multinucleated giant cells (positive Tzanck smear). Skin biopsy would show acantholysis (loss of intercellular connections between keratinocytes) and intraepidermal vesicles.
(Choice A) Acantholysis forming suprabasal blisters is characteristic of pemphigus vulgaris. Immunofluorescence reveals deposition of IgG-containing deposits in a reticular pattern around keratinocytes (targeting desmosome protein desmoglein 3).
(Choice B) Infection by molluscum contagiosum, a poxvirus, causes eosinophilic cytoplasmic inclusions (molluscum bodies) in infected cells and dome-shaped, umbilicated papules on examination.
(Choice C) Human papillomavirus infection of the skin presents with warts (verruca vulgaris) or squamous cell carcinoma of the penis or vulva, depending on the serotype. Light microscopy reveals cytoplasmic vacuoles in keratinocytes (koilocytosis) and epidermal hyperplasia.
(Choice D) Dermatitis herpetiformis presents with pruritic, grouped vesicles on the extensor surfaces. Light microscopy reveals accumulations of neutrophils on the tips of dermal papillae (microabscesses).
Educational objective:
Herpes zoster (shingles) develops due to reactivation of varicella zoster virus in the dorsal root ganglia (sensory neurons). It presents with a painful vesicular rash in a dermatomal distribution. Intranuclear inclusions in keratinocytes and multinucleated giant cells are seen on light microscopy.