Histopathology of Hand–Foot–Mouth Disease in Adults and Criteria for Differentiation From Erythema Multiforme

Histopathologic Findings of Evolving Mpox Lesions

ABSTRACT

This article reports two cases of the 2022 mpox virus with notable histopathology, and includes a novel description of mpox pseudotumor in the perianal region which is not previously described. This article additionally includes literature review of characteristic histopathology through evolving lesions, as it is sparsely described in relation to the 2022 mpox outbreak. Case one describes a 42-year-old man who presented with umbilicated, smooth papules on the trunk and extremities, and milia-like papules on the face. Histopathology of an umbilicated lesion revealed epidermal acanthosis with keratinocyte pallor, ballooning degeneration, keratinocyte necrosis, and neutrophilic epitheliotropism. Case two describes a 51-year-old man who presented with scattered eroded papules as well as a perianal mass. Histopathology of the mass revealed ulceration with keratinocyte enlargement and pallor with a mixed inflammatory cell infiltrate. It additionally revealed rare multinucleated keratinocytes with nuclear molding. These cases are remarkable and contribute to literature as reports of the histopathology of the atypical 2022 mpox outbreak are rare. A combination of clinical, laboratory, and histopathologic evidence is useful in diagnosing mpox, and these cases contribute to describing the evolution of viral lesions.

A case of coxsackievirus A16-induced hand-foot-mouth disease mimicking erythema multiforme

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Hand-Foot-Mouth Disease in an Adult

Hand-foot-mouth syndrome is a common childhood illness. Although occurrence in adults is rare, its incidence has been increasing. In such cases, it usually presents with atypical symptoms. The authors present the case of a 33-year-old male patient who presented with constitutional symptoms, feverish sensation, and macular palmoplantar rash associated with oral and oropharynx ulcers. The epidemiological history revealed exposure to two cohabitants (children) with a recent diagnosis of hand-foot-mouth disease (HFMD).

[New aspects in the histopathology of infectious skin diseases]

BACKGROUND

An infectious pathogenesis should always be considered in inflammatory infiltrates in the skin. While some organisms can be recognized on hematoxylin-eosin staining (e.g. yeasts, leishmania), histochemical and immunohistochemical stainings are available for others.

OBJECTIVES

If no organisms are seen in a section, the diagnosis of an infection cannot be made with surety, but the pattern of the inflammatory infiltrate can still be suggestive of an infectious process. New or little-known reaction patterns and difficulties in differential diagnosis will be demonstrated.

MATERIALS AND METHODS

Selective literature review and analysis of individual cases.

RESULTS

Studies using molecular techniques to identify organisms in biopsy specimens have helped to better characterize the histomorphological spectrum of skin infiltrates in infectious skin diseases. Apart from unusual herpes simplex and varicella zoster infections, the histopathology of coxsackie virus and measles exanthem, borreliosis, syphilis, and of cutaneous leishmaniasis is demonstrated. For numerous organisms, molecular tests have been established that can be used on the formalin-fixed, paraffin-embedded material.

CONCLUSIONS

Selected skin infections demonstrate the broad histomorphological spectrum of skin infiltrates induced by infectious organisms. It is important for histopathologists to know which reaction pattern requires them to alert the clinician to necessary ancillary diagnostics (culture, serology) and when to consider molecular diagnostics to be performed on the biopsy specimen.

Coxsackievirus A6-induced Hand-Foot-and-Mouth Disease Mimicking Stevens-Johnson Syndrome in an Immunocompetent Adult

Hand-foot-and-mouth disease, a highly contagious viral infection, occurs more common in children than in adults. However, there was a recent outbreak of Coxsackievirus A6-induced infection with an atypical presentation among the adult population. Stevens–Johnson syndrome is a severe mucocutaneous disease characterized by extensive necrosis and detachment of the epidermis, and this condition is commonly caused by medications. Herein, we describe a 30-year-old male patient taking allopurinol for the management of gout. The patient presented with numerous erythematous papules, vesicles, and patches with mucosal eruptions on the whole body, oral mucositis, and fever, and he was finally diagnosed with hand-foot-and-mouth disease.