PMC6694281_01
Clinical and histopathology appearance of cutaneous Curvularia geniculata. Right forelimb paw swelling with multifocal draining tracts (a,b); Note pyogranulomatous dermatitis with intralesional pigmented fungal elements (asterisk) centered around hair follicles and adnexa (c: 10X, H&E stain); Note the GMS-positive septate fungal elements, which form large, terminal dilations (d: 20X, GMS stain).
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F1
The patient presented just over 6 weeks after initial referral with right forelimb paw swelling and multifocal draining tracts (Figures 1a,b). Examination of H&E stained biopsies showed pyogranulomatous dermatitis with intralesional GMS-positive pigmented fungal elements, centered around hair follicles and adnexa, consistent with phaeohyphomycosis (Figures 1c,d).
Right forelimb improvement after treatment of Curvularia geniculata
(a); Clinical appearance of cutaneous Nocardia niigatensis with diffuse left forelimb edema, nodules and two draining tracts (a, b); Histopathology of cutaneous nocardiosis is characterized by diffuse neutrophilic dermatitis with superficial dermal edema and small numbers of macrophages(c: 4X, H&E stain; d: 20X, H&E stain); Rare, slender gram-positive branching bacilli (arrowheads) scattered throughout the deep dermis with neutrophilic cell infiltration(e: 100X, Gram-stain); Clinical improvement of left forelimb after treatment of cutaneous Nocardiosis (f); Multifocal exophytic cutaneous viral papillomason lateral muzzle (g).
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F2
On progress examination, 4 weeks later (10 weeks from initial presentation), the right forelimb skin lesions completely resolved (Figure 2a), but the patient developed acute diffuse upper left forelimb edema, nodules, and two draining tracts (Figures 2a,b). H&E, Gram, Giemsa, modified Ziehl-Neelsen (ZN), periodic acid-Schiff (PAS), and Warthin-Starry silver stain; fresh tissue from the affected lesional skin was submitted for fungal and bacterial aerobicculture. Histopathologic examination revealed marked diffuse neutrophilic dermatitis with superficial dermal edema and small numbers of macrophages (Figures 2c,d). Argyrophilic, slender Gram- and Giemsa-stain positive branching bacilli were scattered throughout the deep dermis with neutrophilic infiltration (Figure 2e); PAS and modified ZN stains were negative. On progress examination, 3 weeks later (13 weeks from initial presentation), the left forelimb swelling, nodules, and draining tracts improved markedly (Figure 2f), but the patient developed with acute diffuse swelling of the right carpus and several multifocal exophytic cutaneous masses were observed on the face and legs (Figure 2g).
Clinical appearance and histopathology of cutaneous viral exophyticpapillomas. Note the papillary hyperplasia and severe hyperkeratotis (a: 4X, H&Estain). Keratinocytes are enlarged with gray-blue finely fibrillar cytoplasm and sometimes have a large amphophilic, intranuclear inclusion body that peripheralizes the chromatin (b: 20X, H&E stain); Immunohistochemistry staining with anti-human papillomavirus antibodies reveals the presence of papillomaviral L1 positive for viral papillomas (c: 10X; broad spectrum BPV-1/IH8 and CAMVIR-1 antibody). Diffuse to coalescing viral-papillomas on the left forelimb limb and margin of paw pad (d-f); Near regression of viral papillomas of left forelimb after therapy with topical imiquimod (g).
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F3
Surgical removal of the cutaneous masses with histopathology revealed irregular epidermal hyperplasia with intranuclear keratinocyte inclusion bodies characteristic of viral-induced papillomas (Figures 3a-c). About 4 weeks later, the patient presented with development of diffuse to coalescing viral-papillomas (VP) on the left forelimb (Figures 3d-f). Therapy with every other day topical imiquimod (5%; Perrigo; Allegan, MI, USA) resulted in near regression of the lesions 2 weeks later (Figure 3g).