Answers to Image of the Month 2017
Case contributed by Dr V Ramesh
Chromoblastomycosis
There is pseudoepitheliomatous hyperplasia in the epidermis. The dermis shows granulomas, mostly tuberculoid and few suppurative with presence of thick- walled, round, golden-brown fungal cells (sclerotic bodies / muriform cells / Medlar bodies / copper penny bodies) singly and in clusters within giant cells and lying free.Fungi divide by septation rather than budding.
Chromoblastomycosis is a chronic fungal infection of the skin and subcutaneous tissues, usually affecting the limbs at the inoculation site. Causative agents include pigmented fungi found in soil, wood and decaying plant material such as Fonsecaea pedrosi, Phialophora verrucosa, Fonsecaea compacta, Cladophialophora carrionii, Rhinocladiella aquaspersa. Incidence of chromoblastomycosis is greatest in tropical and subtropical regions. Barefooted farmers account for almost 75% of patients with this disease. Commonest clinical presentation is a slowly progressive verrucous plaque over the extremities. Satellite lesions may be present. Rarely, squamous cell carcinoma develops within longstanding cases.
Case contributed by Dr Geeti Khullar
Chondroid syringoma
A well circumscribed, lobulated mass centered in deep dermis or subcutaneous fat, with a prominent chondroid or myxoid stroma enveloping benign bland appearing epithelial and myoepithelial cells that form secondary structures which include glands and ducts, cysts, reticular lace-like network, keratinous cysts and foci of squamous differentiation. Other cells present include plasmacytoid, low cuboidal, spindle, clear cell, cells with follicular, pilomatrical differentiation and mature adipocytes. Though typically chondromyxoid, the background may be focally hyaline. Calcification / ossification may occur. Mitoses are sparse, necrosis is absent.
Chondroid syringoma is a benign tumor of the sweat glands with a myxoid stroma showing cartilaginous metaplasia. Morphologically it is identical to pleomorphic adenoma / benign mixed tumor of the salivary gland. It is most often seen in middle aged men, commonly on the nose, followed by cheek and upper lip.
Case contributed by Dr Mithilesh Chandra
Chronic hyperplastic candidiasis
Acanthosis, parakeratosis, neutrophilic infiltration in the upper layers and numerous fungal buds and pseudohyphae which can be distinctly seen without PAS stain also and mild dysplastic changes in the lower layers of epithelium.
Chronic hyperplastic candidiasis is a chronic inflammatory condition of oral mucosa caused generally by Candida albicans. Clinically it presents as a homogenous white lesion or a speckled or nodular lesion. Microscopically it is characterized by acanthosis, parakeratosis of epithelium and neutrophilic infiltration of parakeratotic layer, which is considered a diagnostic feature. Many cases show dysplastic changes of the epithelium if left untreated for long. Rare cases with dysplasia can progress to malignancy. Hyphae present perpendicular to the epithelium are demonstrated better with the help of PAS stain. Submucosa shows variable intensity of chronic inflammation.
Case contributed by Dr Geeti Khullar
Adult onset Still's disease
There are multiple necrotic keratinocytes lying singly and in aggregates mainly in the upper layers of the epidermis, including the stratum corneum. The upper dermis shows perivascular and interstitial neutrophil-rich inflammatory infiltrate.
Adult onset Still's disease (AOSD) is a rare systemic autoinflammatory disorder, characterised by quotidian or double‐quotidian spiking fever with an evanescent rash, arthritis, and multiorgan involvement. Skin findings accompany the disease in nearly 90% of the cases. The typical rash is an evanescent, salmon‐pink, maculopapular eruption, predominantly found on the proximal limbs and trunk, with rare involvement of the face and distal limbs. A more persistent rash that tends to be photodistributed, hyperpigmented, often in a linear configuration, sometimes in a rippled pattern is referred to as the atypical eruption of AOSD. Consistent laboratory abnormalities include leukocytosis with neutrophilia and hyperferritinemia. Yamaguchi's criteria have been shown to be the most sensitive for diagnosis.
Erythema marginatum associated with rheumatic fever is a type of annular erythema, which is an important histological differential. It shows dyskeratotic keratinocytes all over the epidermis and presence of neutrophils and nuclear dust in the dermal papillae.
Image 1: Case contributed by Dr. Mithilesh Chandra
Granuloma faciale
Dense cellular infiltrate, often with a nodular outline, occupies the mid dermis. Deep dermis and subcutaneous fat may be involved. Typically spares the immediate subepidermis and hair follicles, forming a Grenz zone. Infiltrate is polymorphic, containing eosinophils, neutrophils and an admixture of plasma cells, mast cells and lymphocytes. Red cell extravasation is often present. Blood vessels appear dilated and their walls are infiltrated by eosinophils and fibrin deposition. Older lesions may show fibrosis and hemosiderin deposition. In late stage, histology resembles erythema elevatum diutinum.
Image 2: Case contributed by Dr. Shipra Agarwal
Cylindroma
Poorly circumscribed dermal tumor composed of irregularly shaped islands and cords of basaloid cells surrounded by conspicuous eosinophilic hyaline bands which are PAS positive and diastase resistant. Droplets of similar hyaline material may be present in the cell nests. Most of the tumor islands have two cell types: a peripheral cell with a dark-staining nucleus and a tendency for palisading, and a larger cell with a vesicular nucleus more centrally located. Small duct-like structures are sometimes present. The stroma is composed of loosely arranged collagen. Areas resembling spiradenoma will sometimes be present, and there may also be tumor lobules with overlap features between these two entities.
Subcutaneous phycomycosis. Culture grew Conidiobolus
The epidermis displays follicular plugging and irregular acanthosis. The superficial and mid dermis shows moderate interstitial infiltrates of lymphocytes, plasma cells, eosinophils, histiocytes and few neutrophils and multiple granulomata composed of aggregates of epithelioid histiocytes, lymphocytes with a few multinucleated type giant cells. Also seen deeper in the deep dermis and subcutis are many broad thin walled aseptate fungal hyphae surrounded by smudgy acellular eosinophilic material (Splendore Hoepli phenomenon). There are extensive areas of hyalinisation.
Differential diagnoses: Well's disease and Basidiobolomycosis.
In Well's disease the clear spaces on H&E can resemble the flame figures of eosinophilic cellulitis but are negative on PAS and GMS stains.
Basidiobolomycosis is also an entomophthoromycosis like conidiobolomycosis but is seen predominantly on the skin and subcutaneous tissue and GIT. Conidiobolomycosis is seen in the head and neck region predominantly in the skin of face and sinuses. All entomophthorales look similar on H&E but are different on culture. Entomophorales is seen in immunocompetant individuals unlike zygomycetes which is seen in immunocompromised individuals.
Case contributed by Dr. V Ramesh
Tinea capitis (endothrix)
Hyphae invade the hair shafts. Rounded and boxlike arthrospores are found mainly within the hair shaft in endothrix infections (when they surround the hair shaft like a sheath it signifies ectothrix infection). Endothrix infections are usually caused by T. tonsurans or violaceum. Although hyphae invade the shaft in both types of infection, they may not be evident in hairs plucked from an endothrix infection because the more superficial hyphae rapidly break up into arthrospores and destroy the keratin of the hair shaft. When plucked, the weakened shaft typically breaks at a relatively superficial point so that only the arthrospores are seen. At times the dermis may show chronic inflammation or giant cells around degenerated hair shafts (not seen in this histopathologic picture).
Case contributed by Dr. Mithilesh Chandra
Lichenoid tattoo reaction
As tattooing practices increase, delayed-type inflammatory reactions represent an uncommon adverse event to tattoo pigments. Different reaction patterns, such as eczematous, lichenoid, granulomatous and pseudolymphomatous reactions, have been reported, especially in association with metals contained in red tattoo pigments. The lichenoid tissue reaction to red organic tattoo pigment shows the prototypical features of a cytotoxic inflammatory response to foreign substances (xenobiotics). The lichenoid papular reaction to an organic red tattoo ink, is characterized by an intense mononuclear infiltrate dominated by CD8(+) T cells and CD56(+) lymphocytes and is distributed in the superficial dermis around the red pigment and in the epidermis.
Case contributed by Dr. V Ramesh
Venous lake
The section shows a slightly stretched normal epidermis. The upper dermis shows a large dilated vascular channel with a fibrous wall. The smaller one is lined by flat endothelial cells. A recanalising thrombus is seen to partially occlude the large vessel. The findings suggest a dilated venular segment.
Venous lakes are vascular anomalies of the nature of ectasias. The lesions are dark blue and occur over the facial areas and neck of elderly persons. In this patient it was seen in the lower lip of a young adult. These lesions bleed on trauma and are frequently mistaken for pyogenic granuloma.
Granuloma annulare
Three histological patterns are seen- interstitial (most common), necrobiotic and sarcoidal or tuberculoid. In the necrobiotic form, areas of necrobiosis or altered collagen are surrounded by histiocytes and lymphocytes in superficial and mid-dermis. The rim of histiocytes forms a palisade. Multinucleate giant cells are also present. The necrobiotic area contains mucin, which is seen as basophilic stringy material between the collagen bundles.
Granuloma annulare is a necrobiotic disorder that presents as skin colored to erythematous grouped papules that coalesce to form annular and arciform plaques. The clinical variants include localized, generalized, perforating and subcutaneous forms. The hands, feet, arms and legs are the sites of predilection.
Case contributed by Dr. Mithilesh Chandra
Verruca plana
Focal epidermal hyperplasia with hyperkeratosis, parakeratosis and may have trichilemmal keratinisation. Koilocytes are present in upper spinous layer. These cells are keratinocytes and appear as polyhedral or rounded cells with cytoplasmic vacuole, large cytoplasmic eosinophilic aggregates and pyknotic nuclei. Older lesions may lack cytoplasmic changes. Viral nuclear inclusions are basophilic. Involuting lesions may have chronic inflammatory infiltrates in dermis and epidermis with degenerative epithelial changes. Diagnosis can be confirmed by in situ hybridization for HPV.
Verruca plana is also called flat wart and is usually due to HPV10. Clinically it presents as flat, skin coloured papules which occur in crops / clusters on face and hands. Lesions usually resolve in 6-24 months.
Reticulohistiocytoma
The epidermis is unremarkable. The dermis shows diffuse infiltration with large mononucleated and multinucleated histiocytes, some of which show clear vacuolated cytoplasm and others show moderate to abundant eosinophilic cytoplasm (oncocytic). Amidst these, there are many mature lymphocytes. The periphery of the lesion is well demarcated and shows fibroblastic proliferation. On immunohistochemistry these cells are positive for CD 68 and they are negative for CD 117 and CD1 a.