Skin Infections (Viral) Pathology Notes PDF

PATHOLOGY 09/07/2024. MOD 5: VIRAL SKIN INFECTIONS Dr. Rennan...

PATHOLOGY 09/07/2024. MOD 5: VIRAL SKIN INFECTIONS Dr. Rennan B. Navarro, M.D. Trans Group/s: 1B I. VERRUCAE (WARTS) ○ Plana - meaning flat Caused by human papillomaviruses (HPV) Lesion: slightly elevated, flat, smooth, tan papules Common lesions in children and adolescents, but may that are generally smaller than verruca vulgaris be encountered at any age. Same histologic features as verruca vulgaris but in Generally self-limited, regress spontaneously within 6 verruca plana, papillomatosis is absent months up to 2 years Common on the face and/or the dorsal surfaces of the Transmission: via direct contact or by autoinoculation hand A. CLASSIFICATION BASED ON LOCATION & CLINICAL 3. VERRUCA PLANTARIS AND PALMARIS (Palmoplantar MORPHOLOGY warts) Rough scaly lesions, 1-2 cm in diameter May coalesce and be confused with calluses Verruca vulgaris Can occur at any site Verruca plana Almost flat due to absence of Verruca plantaris Occur on the soles papillomatosis Verruca palmaris Occur on the palms Verruca plantaris / Found in the foot plantar and palm palmaris areas, respectively Palmoplantar wart Occur on both locations (Palmoplantar wart) Lesions found in both locations: 4. CONDYLOMA ACUMINATUM (Venereal or anogenital Palmoplantar wart warts) Condyloma When verrucae involves anal, Also known as the venereal or anogenital wart acuminatum perianal, and genital areas Occurs on the penis, female genitalia, urethra, perianal area, rectum 1. VERRUCA VULGARIS (Common warts) Low risk oncogenic HPV: ○ HPV 6, 11 causes/associated with condyloma Also known as the common wart acuminata Occurs at any site but most frequently on the dorsal High risk oncogenic HPV: aspect of the fingers and hands ○ HPV 16, 18, 31, 33, 35 most common Associated with HPV-2, 4, and 7 causes/associated with anogenital squamous cell Lesion: painless, can be pruritic, circumscribed, firm, carcinoma elevated papules (1-10 mm in size) with The most frequent cause is HPV-16 papillomatous (“verrucous”) hyperkeratotic surfaces The least frequent cause is HPV-18 Generally self-limited but may persist for a few months Lesions: appear as soft, tan, cauliflower-like masses or up to several years Notorious for autoinoculation or Koebner Phenomenon 1.1 Koebner phenomenon The formation of new warts at sites of trauma, especially if the patient used to scratch the lesions Condyloma Acuminatum. B. HISTOPATHOLOGY 1. CONDYLOMA ACUMINATA Verruca vulgaris. 2. VERRUCA PLANA (Flat warts) Also known as the flat wart Pathology - Mod 5 Viral Skin Infections 1 of 5 The use of trans, practice questions, and evals ratio must be used discreetly and social media/public exposure of the aforementioned shall be strictly prohibited.  2.1 Koilocytic Cells Koilocytes: small, round, deeply basophilic nuclei surrounded by a clear halo and pale-staining cytoplasm ○ Atypical-looking but not malignant or neoplastic Hyperchromatic nuclei Irregular in shape rather than round to ovoid Angulated This vacuolization of the keratinocytes is in response to the effects of the virus in the skin, particularly in the upper stratum malpighi and in the granular layer. Generically, it is a form of viral cytopathic effect Condyloma Acuminata. Microscopically on a scanning view of the Condyloma, it shows a white cauliflower-like lesion with numerous papillary or polypoid fronds as indicated by the black arrows. Koilocytic Cells. Condyloma Acuminata. Enclosed in the yellow broken lines is a papillary frond Koilocytes (pointed by the black arrow). On high power magnification of the papillary frond, the central core, which is fibrovascular, and the surface 2.2 Clumped Keratohyaline Granules epithelial covering is composed of mature keratinocytes of which many have vacuolated cytoplasm with small deeply basophilic or raisin-like nuclei, morphologically called koilocytes 2. VERRUCAE (IN GENERAL) GENERAL PRESENTATION OF VERRUCAE 1 Acanthosis 2 Papillomatosis (except in verruca plana) 3 Parakeratosis Clumped Keratohyaline Granules in the Stratum Granulosum. 4 Hyperkeratosis 5 Hypergranulosis II. HERPES SIMPLEX INFECTION Other histopathologic characteristics are the presence of koilocytic cells and clumped keratohyaline granules. Serologic Types HERPES SIMPLEX VIRUS HERPES SIMPLEX VIRUS TYPE 1 (HSV-1) TYPE 2 (HSV-2) Orofacial type Genital type Causes: Causes: Acute Herpes genitalis Gingivostomatitis Herpes Labialis or Cold General Characteristics of Verrucae. Sores – affecting the lips, oral mucosa Pathology - Mod 5 🏠 Viral Skin Infections 2 of 5 The use of trans, practice questions, and evals ratio must be used discreetly and social media/public exposure of the aforementioned shall be strictly prohibited.  Later, degeneration of epithelial cell → acantholysis The virus is transmitted through the exchange of Intraepithelial vesicles (blisters) formed by saliva, semen, cervical fluid, or vesicle fluid from the intracellular edema and ballooning degeneration of active lesions. epidermal cells. Causes acute infection followed by late infection with Diagnosed using clinical history and Tzanck smear periodic reactivation and shedding of infectious virus 1. BALLOON CELL DEGENERATION Characterized by cytoplasmic swelling of the A. PATHOGENESIS epidermal cell with loss of intercellular bridges → Produces acute and latent infections acantholysis Replicate in the skin and mucous membranes at the site of entrance (usually in the oropharynx or genitals) ○ It is also where they usually produce infectious virions resulting in vesicular lesions of the epidermis Spread to sensory neurons that innervate primary sites of replication and establish latent infection Recurrent infection can result from either reactivation of a latent infection or a new infection B. CLINICAL MANIFESTATIONS Manifest clinically as blisters and vesicles around mucosal orifices (very COLD painful) SORES Formed due to intercellular edema Balloon Degeneration of the Epidermal cells (Epidermal cells and ballooning degeneration of the appear vacuolated or space-like due to cytoplasmic epidermal cells swelling). Usually encountered in children 2. COWDRY TYPE A INCLUSION Caused by HSV type 1 A characteristic microscopic finding in HSV is the Presents with vesicular eruptions presence of inclusion bodies. GINGIVO- STOMATITIS extending from the tongue to the They are large, pink to purple intranuclear inclusions retropharynx which contain intact and disrupted virions. May present with cervical lymphadenopathy Caused by HSV type 2 Presents with vesicles on the genital mucous membranes and the external genitalia which are rapidly converted into superficial ulcerations GENITAL HERPES When these vesicles burst, it will eventually ulcerate. Can be transmitted to neonates affecting eyes (herpes keratitis) during passage through the birth canal Cowdry Type A Inclusions. of infected mothers 3. MULTINUCLEATED GIANT CELLS (POLYKARYONS) Also called polykaryons Contains several nuclei seemingly sharing one big cytoplasm Cold Sores, Gingivostomatitis, and Genital Herpes. Multinucleated Giant Cells (Polykaryons). C. HISTOPATHOLOGY The earliest change in the skin is nuclear swelling of D. SPECIAL CUTANEOUS FORMS CAUSED BY HSV keratinocytes along the basal layer then involving the INFECTION entire epidermis Pathology - Mod 5 🏠 Viral Skin Infections 3 of 5 The use of trans, practice questions, and evals ratio must be used discreetly and social media/public exposure of the aforementioned shall be strictly prohibited.  Vesicles are painful, deep-seated, Complications: pneumonitis, encephalitis limited to the paronychia or volar More concentrated on the trunk and back aspects of the distal phalanx of the Less on the extremities HERPETIC WHITLOW finger. Occurs largely in medical and dental personnel following minor injuries May be caused by HSV-1 or HSV-2 Lesions are confluent, pustular or hemorrhagic blisters ECZEMA Often with bacterial superinfection HERPETICUM and viral dissemination in the internal viscera Potentially life-threatening Chicken Pox. Herpetic whitlow (L) and Eczema Herpeticum (R). III. VARICELLA ZOSTER Chicken Pox (crust formation). Black arrow: Crust Formation. Varicella zoster virus causes chickenpox and shingles 2. SHINGLES (HERPES ZOSTER) PRIMARY/ACUTE Shingles occurs when the varicella zoster virus that has INFECTION FORM Causes chicken pox (varicella) long remained latent in the dorsal root ganglia is reactivated and infects the sensory nerve that carries it REACTIVATED FORM Causes shingles (herpes zoster) to one or more dermatomes Skin disease is commonly seen in immunocompromised elderly who had varicella A. PATHOGENESIS before. Infection is epidemically transmitted via aerosols. Clinically, patients present with vesicular lesions, Can disseminate hematogenously causing intense itching and burning or sharp pain due to widespread vesicular skin lesions radiculoneuritis with the nerve roots and their attended Infects mucous membranes, skin, and neurons, and peripheral nerves are inflamed. establishes latent infection in the sensory ganglia Ramsay Hunt syndrome: (like HSV) ○ Some patients may exhibit this condition ○ The virus can also infect neurons and satellite ○ Involvement of geniculate nucleus (nerve roots of cells around neurons in the dorsal root ganglia spinal cord) resulting in facial paralysis manifested and may recur (reactivated) many years after the in patients primary infection, causing shingles. Self-limited primary infection among 2.1 Morphology of Shingles (Herpes Zoster) immunocompetent individuals Grossly, the lesion occurs in grouped vesicles along Localized recurrence is most frequent and most painful the course of a sensory nerve (dermatomal line) in dermatomes innervated by trigeminal ganglia where ○ Lesser lesions but more painful the virus is most likely to exist in a state of latency Vesicle bases are frequently hemorrhagic, some In contrast to numerous recurrences of HSV, VZV necrotic and have ulceration usually recurs only ONCE, commonly in Some lesions are indistinguishable from varicella immunosuppressed or elderly persons 1. CHICKEN POX (VARICELLA) 90% of cases occur in children (≤ 14 y/o) Rashes occur approximately 2 weeks after respiratory infection Has a centrifugal distribution ○ Each lesion progresses rapidly from a macule → a vesicle (resembling a dewdrop on a rose petal) Vesicle contains intranuclear inclusions which are infectious ○ When vesicles rupture, crest form over and the lesions heal by regeneration Shingles. Black arrows: Grouped vesicles spanning along a Vesicles rupture → crust over → heal by course of sensory nerve. regeneration Lesions in varying stages occur one at a time Pathology - Mod 5 🏠 Viral Skin Infections 4 of 5 The use of trans, practice questions, and evals ratio must be used discreetly and social media/public exposure of the aforementioned shall be strictly prohibited. B. HISTOPATHOLOGY Epidermal keratinocytes exhibiting balloon Examination of the ganglia will reveal degeneration and intranuclear inclusions lymphoplasmacytic infiltrates and the presence of Acantholytic cells: detached keratinocytes with intranuclear inclusions within the neurons small dark nuclei Lesions of varicella and herpes zoster indistinguishable from those of herpes simplex infection Tzanck smear. Herpes Zoster. Lymphoplasmacytic infiltrates. IV. MOLLUSCUM CONTAGIOSUM A common, self limited, skin infection caused by poxvirus. Transmission: ○ Directly via bodily contact ○ Indirectly via fomites Multiple lesions on the skin and mucous membranes (especially, trunk and anogenital areas) A. MORPHOLOGY Herpes Zoster. Black arrow (Inclusion body). Molluscum contagiosum (umbilicated papules). Lesions are firm, often pruritic, pink to skin colored umbilicated papules (0.2-0.4cm), in which a curd-like material can be expressed from the umbilication. ○ The curd-like material is very infectious. Microscopic lesions in varicella or herpes zoster showing the intraepithelial vesicles. B. HISTOLOGY TZANCK SMEAR One of the easiest, fast and cheap test to diagnose herpes infection ○ Not only VZV but also HSV Cytologic examination of a Giemsa-stained smear taken from the floor of a freshly-opened early vesicle In this test, we choose a lesion that is intact or still vesicular. 1 The vesicle is ruptured using a sterile lancet lifting the thin membranous covering thereby exposing the base of the lesion. 2 A sterile cotton pledget is used to swab or scrape off the base to collect samples. Molluscum bodies. 3 Swabs are smeared on a glass slide, then pasted in a canister with alcohol fixative. Molluscum bodies: large, ellipsoid (or ovoid), pinkish, homogenous, cytoplasmic inclusions in the cells of the 4 Smears are then stained and covered with cover stratum granulosum and corneum. slips. ○ These bodies contain numerous (millions) 5 Microscopic evaluation to look for: virions. Multinucleated giant cells Pathology - Mod 5 🏠 Viral Skin Infections 5 of 5 The use of trans, practice questions, and evals ratio must be used discreetly and social media/public exposure of the aforementioned shall be strictly prohibited.