Dermpedia

Sharing dermatology and dermatopathology knowledge

Onychomycosis is a frequently treated fungal infection of the nail plate with morbidity in high-risk populations. The diagnosis often relies on histopathologic analysis of nail plate specimens with the assistance of special stains. Pathologists utilize periodic acid schiff (PAS) and/or Gomori methenamine silver (GMS) stains to highlight fungi within the nail plate. In a recent study of 51 PAS-negative nail cases, it was concluded that GMS is superior to PAS in the diagnosis of onychomycosis. We expand on this study by investigating a larger number of PAS-negative nail clippings determining whether GMS or PAS is superior in highlighting fungi in additional sections. There was no difference in the sensitivity of PAS vs. GMS (4.2 vs. 4.3%, p = 0.57); however, PAS was found to be significantly less expensive by 2.6-fold. Taken together, these data suggest that the PAS stain is the optimal method for diagnosing onychomycosis.Barak O, Asarch A, Horn T. PAS is optimal for diagnosing onychomycosis.

Background: Onychomycosis is the most common nail disease in adults. Periodic acid-Schiff (PAS) stain has been considered the most sensitive method for diagnosis. By comparing originally stained PAS slides (i.e. without repeating PAS) with newly stained Grocott methenamine-silver (GMS) slide, D’Hue et al. concluded that GMS is superior to PAS. We conducted a similar study with the addition of repeating PAS stain and compared the newly stained PAS and GMS slides in tandem.Methods: We performed both PAS and GMS stains on 30 clinically suspected onychomycosis cases. The presence or absence of fungal organisms was evaluated. The results were also compared with the original PAS stain.Results: Twenty-two cases were positive with PAS, staining three cases more than GMS, which stained only 19 cases. The difference between the two stains is statistically insignificant. Repetition of GMS stain on these three cases (cutting in a deeper level in the paraffin block) resulted in positive results. Four out of 30 cases were negative with original PAS stain, but stained positive both with new PAS and GMS.Conclusions: PAS and GMS stains are quantitatively similar. Sensitivity of both methods can be increased by preparing two slides from different levels in the paraffin block.Reza Kermanshahi T, Rhatigan R. Comparison between PAS and GMS stains for the diagnosis of onychomycosis.

Background: Epithelioid hemangioma (EH) is a benign vascular proliferation usually accompanied by a mixed inflammatory infiltrate.Methods: Skin biopsy specimens from four patients with EH on the extremities were studied. Architecture, extent of vascular proliferation and the presence of epithelioid endothelial cells were evaluated. The features of the inflammatory infiltrate were also assessed, including the distribution, depth, predominant cell type, presence of germinal centers, and distribution and number of CD30+ cells.Results: All cases showed the typical lobular pattern of small vessels centered about a ‘feeder’ vessel. Larger vessels were lined by epithelioid endothelial cells. The mixed inflammatory infiltrate was nodular, perivascular and periadnexal. Germinal centers were seen in two cases. Large activated CD30+ lymphocytes were seen in all cases.Conclusions: EH can lead to diagnostic confusion with cutaneous lymphoma and other entities, especially when its mixed inflammatory infiltrate predominates over its vascular component and contains large activated CD30+ lymphocytes. Awareness that the presence of CD30+ activated lymphocytes is not specific for lymphoma and recognition of the vascular component is critical for proper diagnosis of EH.Cham E, Smoller BR, Lorber DA, Victor TA, Cibull TL. Epithelioid hemangioma (angiolymphoid hyperplasia with eosinophilia) arising on the extremities.

Background: Perineuriomas are an uncommon group of tumors composed of perineurial cells of peripheral nerve sheath lineage. Variants include soft tissue (extraneural), intraneural, sclerosing, reticular and plexiform forms. Sclerosing perineuriomas have been reported to occur almost exclusively on the hands of young men. Herein, we report three extra-acral cutaneous/soft tissue perineuriomas that show significant associated sclerosis.Methods: Skin biopsy specimens from three patients were evaluated for cytomorphology and degree of associated sclerosis, which was classified as either focal or diffuse. Immunohistochemical expression of epithelial membrane antigen (EMA), CD34 and S-100 was also assessed to facilitate further classification.Results: Histopathologically, the tumors showed both focal and diffuse sclerosis, and lesional cells were generally spindled in shape. Immunohistochemical staining showed diffuse positivity for CD34 and focal or diffuse positivity for EMA. The cells uniformly lacked expression of S-100 protein.Conclusions: Sclerosing perineuriomas can occur in extra-acral locations and should be considered in the differential of EMA-positive cutaneous spindle-cell proliferations. It is also important to recognize that perineuriomas can express CD34 and should be considered in the differential diagnosis of CD34-positive cutaneous neoplasms.Fox M, Gleason BC, Thomas AB, Victor TA, Cibull TC. Extra-acral cutaneous/soft tissue sclerosing perineurioma: an under-recognized entity in the differential of CD34-positive cutaneous neoplasms.

Background: Trichoblastomas (TBs) are benign follicular tumors that can present either as solitary nodule or as multiple facial papules. Only one case of sporadic TB in a composite tumor has been reported, arising in an apocrine poroma. We report the association of TB and benign epidermal/follicular neoplasm in six patients.Methods: Clinical data available were collected. Serial sections and immunohistochemical (IHC) analysis for CK17 and human papilloma virus (HPV) were performed on available materials.Results: Five of the six patients were males. Mean age at diagnostic was 56 years. Lesions were localized on the face and scalp in four of six patients. The lesions associated with TB were inverted follicular keratosis (IFK) in three cases, seborrhoeic keratosis (SK) in two cases and IFK with verruca vulgaris pattern in one case. IHC for HPV was negative in the four cases tested. Staining for CK17 was always positive in TB. It was often positive in the associated neoplasm.Conclusion: TB can be associated with benign epidermal/follicular neoplasm in composite tumors. The association of TB and IFK with direct connection between the lesions is another argument in favor of the follicular origin of IFK. TB can be added to the spectrum of SK-associated tumors.Battistella M, Peltre B, Cribier B. Composite tumors associating trichoblastoma and benign epidermal/follicular neoplasm: another proof of the follicular nature of inverted follicular keratosis.

Cutaneous complications occur not uncommonly in patients with Crohn's disease (CD). Gastrointestinal CD often shows non-caseating granulomas and a rare cutaneous finding in CD is a sterile granulomatous infiltrate not contiguous with the GI tract, termed extraintestinal CD (ECD). The clinical presentation of ECD is diverse. The most common histopathological presentation is a superficial and deep granulomatous infiltrate that often accompanies a mixed perivascular infiltrate. Here we report two patients with CD and skin lesions characterized on microscopy by granulomatous vasculitis. A 29-year-old female presented with papules and ulcerated nodules above the ankle. The biopsy showed dermal and superficial subcutaneous involvement by a vasocentric infiltrate of mononuclear and multinucleated histiocytes as well as mural fibrin deposition. A 35-year-old male presented with two tender indurated erythematous plaques with punched-out centers on the lower leg. Histopathologically, a granulomatous vasculitis of small and medium-sized vessels in the dermis and subcutis was evident. These two cases represent the rarely described phenomenon of cutaneous granulomatous vasculitis in CD. Previously reported examples of this entity are reviewed.Burns AM, Walsh N, Green PJ. Granulomatous vasculitis in Crohn's disease: a clinicopathologic correlate of two unusual cases.

Scleromyxedema is the generalized and sclerodermoid form of lichen myxedematosus. Its typical histological features include a diffuse deposition of mucin in the papillary and mid reticular dermis, an increased of collagen deposition, and a proliferation of irregularly arranged fibroblasts. We describe a 76-year-old man presenting with scleromyxedema associated with IgGλ monoclonal gammopathy whose biopsy showed histological features of an interstitial granulomatous-like process consistent with interstitial granuloma annulare. The significance of these unusual granulomatous findings in the setting of scleromyxedema are unknown and have been described only once in the literature. This observation expands the spectrum of scleromyxedema and highlights the difficulty in diagnosing this disabling condition.Rongioletti F, Cozzani E, Parodi A. Scleromyxedema with an interstitial granulomatous-like pattern: a rare histologic variant mimicking granuloma annulare.

Anaplastic Kaposi sarcoma (KS) is an uncommon histologic phenotype of Kaposi's and one that is typically associated with a locally aggressive clinical course. We report a case of a 53-year-old human immunodeficiency virus-positive male, on highly active antiretroviral therapy 1 month prior to admission, who presented with fever, cough, respiratory distress, multiple skin lesions and cervical and inguinal lymphadenopathy not responding to multiple antibiotics. Microscopic examination of punch biopsies from the forehead and chest revealed a spindled cell neoplasm with marked cytologic atypia and scattered mitoses, features consistent with a diagnosis of anaplastic KS and confirmed by immunohistochemistry with HHV-8. Biopsy of an involved lymph node also revealed involvement by KS. Despite aggressive clinical treatment, the patient rapidly deteriorated and expired 1 week after the diagnosis of anaplastic KS was rendered. Our case underscores the aggressive clinical course of this uncommon histologic variant of KS and its recalcitrant clinical behavior.Yu Y, Demierre M-F, Mahalingam M. Anaplastic Kaposi's sarcoma: an uncommon histologic phenotype with an aggressive clinical course.

Palisaded neutrophilic granulomatous dermatitis (PNGD) is a rare dermatologic condition which shows various clinical and histopathological features. Although the PNGD lesions have been suggested to begin as leukocytoclastic vasculitis (LCV), there is still insufficient clinicopathological information in the reported cases of PNGD in acute stage with LCV. The relationship between PNGD and interstitial granumatous dermatis (IGD) also remains unclear. This report presents the case of a 60-year-old female patient with multiple erythematous nodules on the extremities. She had no underlying systemic disease detected to date, although transient, abnormal liver function tests were seen. The histopathological examination of an erythematous nodule revealed the features of PNGD in the acute stage. The patient presented the characteristic features of LCV including palisaded granulomatous pattern, and the interstitial granulomatous pattern was seen together, suggesting that PNGD with LCV can show an interstitial granulomatous pattern. The present case also suggested that PNGD in the acute stage with LCV tends to clinically manifest as erythematous nodules on the extremities and histopathologically shows a remarkable papillary edema and an extensive fibrin deposition in and around the vessel wall. PNGD may be associated with transient liver dysfunction.Misago N, Shinoda Y, Tago M, Narisawa Y. Palisaded neutrophilic granulomatous dermatitis with leukocytoclastic vasculitis in a patient without any underlying systemic disease detected to date.

Herpes zoster (shingles) is the result of a reactivation of the varicella zoster virus (VZV). Many adults obtain a VZV vaccine in order to prevent zoster. Non-specific injection site reactions and generalized herpes eruptions have been reported to occur, especially in immunocompromised patients. However, these are most often anatomically generalized reactions and histopathologically resemble typical herpes infections. We report a 61-year-old female on immunosuppressant medications for rheumatoid arthritis who presented with a subcutaneous nodule at the site of a recent herpes zoster vaccination. Histopathological examination revealed a dense nodular and interstitial mononuclear infiltrate throughout the mid and deep dermis with extension into the superficial subcutaneous fat. Immunohistochemical staining revealed an admixture of T-cells and B-cells, with a predominance of T-cells. These findings are consistent with a pseudolymphoma (PL), a reactive inflammatory disorder that can resemble cutaneous lymphoma and has rarely been described in herpes infections and post-herpetic scars. In situ hybridization studies for VZV were performed and highlighted occasional deep fibroblasts with nuclear positivity for VZV DNA. A review of post-vaccination reactions and herpes-related PL is discussed with emphasis on using in situ hybridization in establishing the diagnosis.Porto DA, Comfere NI, Myers LM, Abbott JJ. Pseudolymphomatous reaction to varicella zoster virus vaccination: role of viral in situ hybridization.

Large-cell acanthoma (LCA) is a sharply demarcated epidermal lesion composed of large keratinocytes and characterized by hyperkeratosis, hypergranulosis and orthokeratosis. It usually affects actinically damaged skin. LCA is currently believed to be a distinct entity with an unclear pathogenesis and a benign biologic behavior. Here, we describe the first occurrence of LCA in the conjunctiva. The lesion recurred following initial excision, and later recurred as a carcinoma in situ following a second excision. This case suggests that LCA may have a malignant and transformation potential.Ghazi NG, Patel BS, Olsakovsky Leslie A, White K, Patterson JW. A conjunctival lesion with histological features similar to large-cell acanthoma of the skin.