Herpes Incognito Most Commonly Is Herpes Zoster and Its Histopathologic Pattern Is Distinctive!

[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.

Eosinophils are surprisingly common in biopsy specimens of cutaneous herpes simplex virus and varicella zoster virus infections: Results of a comprehensive histopathologic and clinical appraisal

BACKGROUND

While usually straightforward, diagnostic features of cutaneous herpes simplex virus and varicella zoster virus infection (HSV/VZV) are not always present in biopsy specimens. Although intuitively the presence of eosinophils may lead the pathologist away from the diagnosis of cutaneous HSV/VZV infection, in our practice we have noted that eosinophils are often encountered in diagnostic specimens.

METHODS

To deduce the frequency with which the inflammatory response accompanying cutaneous HSV/VZV infection includes significant numbers of eosinophils, we performed a retrospective review. We included 159 specimens from our database, diagnosed between 2009 and 2017. We determined the number of eosinophils in 10 high-power fields and noted additional histologic factors including presence of follicular involvement, ulceration, and pseudolymphomatous change.

RESULTS

Of all included cases, 63% had 0-1 eosinophils, 24% had 2-10 eosinophils, and 13% had more than 10 eosinophils. Statistical analysis did not reveal a significant association between any demographic or histologic features examined and the presence of increased eosinophils.

CONCLUSIONS

In this study, more than one-third of biopsy specimens diagnostic of cutaneous HSV/VZV infection had a prominent number of eosinophils. The detection of eosinophils should not be unexpected and should not lessen diagnostic suspicion for cutaneous HSV/VZV infection.

[Relevance of biopsies for the diagnostics of infectious skin diseases]

Pathogen-related skin infections are a common problem in the dermatological practice. Apart from culturing and serological detection methods, a skin biopsy is a possible diagnostic procedure, especially when the clinical picture is unspecific and other non-infectious skin diseases are considered as possible differential diagnoses. Some organisms can already be detected by routine staining methods (hematoxylin & eosin, e. g., yeasts, Leishmania), for others numerous histochemical and immunohistochemical stains are available, e. g. periodic acid-Schiff reaction (PAS) and Grocott for hyphae and spores, Ziehl-Neelson and Fite-Faraco for Mycobacteria or specific antibodies for Treponema pallidum or herpesviruses. In other instances, an infectious disease may not be diagnosed with certainty in a histological section but the pattern of inflammatory infiltrates is highly suggestive of an infectious cause. Based on such reaction patterns, the dermatopathologist can advise the clinician to perform cultures or serological investigations or additional molecular biological techniques can be applied to the biopsy specimen in order to identify the pathogens. This article presents skin infections with their histopathological features and highlights diseases that can be diagnosed with certainty in a biopsy and those in which a biopsy is helpful to exclude differential diagnoses or to perform molecular diagnostics on the specimen.

Cutaneous Pseudolymphoma

The term, cutaneous pseudolymphoma (PSL), refers to a group of lymphocyte-rich infiltrates, which either clinically and/or histologically simulate cutaneous lymphomas. Clinicopathologic correlation is essential to achieve the final diagnosis in cutaneous PSL and to differentiate it from cutaneous lymphomas. A wide range of causative agents (eg, Borrelia, injections, tattoo, and arthropod bite) has been described. Based on clinical and/or histologic presentation, 4 main groups of cutaneous PSL can be distinguished: (1) nodular PSL, (2) pseudo-mycosis fungoides, (3) other PSLs (representing distinct clinical entities), and (4) intravascular PSL. The article gives an overview of the clinical and histologic characteristics of cutaneous PSLs.

Vulvar dermatoses: a histopathologic review and classification of 183 cases

BACKGROUND

Vulvar dermatoses are often difficult to classify due to histopathologic overlap. We aimed to report our experience at a single institution.

METHODS

A total of 183 non-neoplastic, non-infectious vulvar biopsies were reviewed. Associations between histopathologic features and specific diagnoses were analyzed by Chi-squared tests.

RESULTS

Twenty-two biopsies (12.0%) showed two concurrent processes. A limited differential rather than a definitive diagnosis was rendered in 15 cases (8.2%). The final diagnoses included lichen sclerosus (LS) (38.8%), lichen simplex chronicus (LSC) (29.0%), eczematous dermatitis (23.0%), Zoon vulvitis (8.2%), non-specific/resolved dermatitis (5.5%), hidradenitis suppurativa (2.7%), Behçet disease (2.2%), lichen planus (1.6%), ruptured cyst (1.6%), ulcer not-otherwise-specified (1.6%), psoriasis (1.1%), radiation dermatitis (1.1%), sebopsoriasis (1.1%), seborrheic dermatitis (1.1%), epidermolytic hyperkeratosis (0.5%) and granular parakeratosis (0.5%). Early LS and Zoon vulvitis were commonly included as part of a differential diagnosis. LS was associated with wiry collagen with lymphocyte entrapment (p = 0.0188). LSC was associated with zones of pale epithelium (p = 0.0084), and often displayed prominent fibroblasts (p = 0.0555). Zoon vulvitis was frequently misdiagnosed, and was associated with basal keratinocytic crowding (p < 0.0001).

CONCLUSIONS

Our study has determined the relative frequencies of a wide variety of vulvar dermatoses, and identified new diagnostic clues for early LS, LSC and Zoon vulvitis.

The role of sensory fiber demography in trigeminal and postherpetic neuralgias

In this study, we systematically investigated fiber demography, based on function and distribution, from the periphery to their destinations in the various central (sub) nuclei in the trigeminal brainstem nuclear sensory complex. Conventional and novel compelling information is provided, demonstrating that the ratio and somatotopy of types A and C sensory fibers at the site of a lesion can elucidate important puzzles in TNP disorders. For instance, we explain how of a major shift in the fibers' direction and ratio at the level of the trigeminal root entry zone (REZ) influences the pathophysiology of pre- and typical trigeminal neuralgia. As a result, there is a high A/C ratio of oral and peri-oral fibers in the supero-medial region of the REZ, which is mostly susceptible to vascular compression. However, this A/C ratio varies considerably at lower proportions in other areas along the peripheral trigeminal pathway, where an injury (viral, vessel compression, or trauma) can lead to a broader spectrum of fiber involvement and, consequently, pain outcome. In summary, we explain how fiber demography can influence pain quality, location, temporal features, progress, and treatment prognosis of TNP in those patients who develop it.

Cutaneous lumbosacral Herpes simplex virus among patients hospitalized for an advanced disease

BACKGROUND

Cutaneous Herpes simplex virus (HSV) infections are regularly observed in lumbosacral areas, and many are refractory to appropriate initial diagnosis and management.

OBJECTIVE

We aimed to evaluate the incidence of lumbosacral HSV among advanced disease patients, to estimate their survival index from HSV onset, and to describe their clinical and virological characteristics.

METHODS

A prospective, descriptive study was conducted in a palliative and continuous care centre, collecting patients with suspected cutaneous HSV lesions in the lumbosacral area.

RESULTS

From 2008 to 2010, 24 patients were included: 19 had HSV-2 confirmed by at least one laboratory test. Incidence of HSV-2 was 2.67% (1.73-4.33%, 95% CI). No age, gender or survival differences were observed compared to the global population in the centre. Most lesions were detected early as vesicles (14/24) or small ulcers. Sensitivity was good for all diagnostic methods (62.5% for immunofluorescence and 79.2% for culture and/or PCR). Outcome was favourable under classical antiherpetic drugs and topical antiseptic dressing.

CONCLUSIONS

Cutaneous lumbosacral HSV remains uncommon in patients hospitalized with advanced diseases. Most of these patients suffer from pressure ulcers or other dermatitis; we advocate increased attention of this diagnosis to avoid skin complications and added pain.