Muhammad N. Mahmood

Automated Segmentation of the Melanocytes in Skin Histopathological Images

In the diagnosis of skin melanoma by analyzing histopathological images, the detection of the melanocytes in the epidermis area is an important step. However, the detection of melanocytes in the epidermis area is difficult because other keratinocytes that are very similar to the melanocytes are also present. This paper proposes a novel computer-aided technique for segmentation of the melanocytes in the skin histopathological images. In order to reduce the local intensity variant, a mean-shift algorithm is applied for the initial segmentation of the image. A local region recursive segmentation algorithm is then proposed to filter out the candidate nuclei regions based on the domain prior knowledge. To distinguish the melanocytes from other keratinocytes in the epidermis area, a novel descriptor, named local double ellipse descriptor (LDED), is proposed to measure the local features of the candidate regions. The LDED uses two parameters: region ellipticity and local pattern characteristics to distinguish the melanocytes from the candidate nuclei regions. Experimental results on 28 different histopathological images of skin tissue with different zooming factors show that the proposed technique provides a superior performance.

Detection of melanocytes in skin histopathological images using radial line scanning

In the diagnosis of skin melanoma by analyzing histopathological images, the detection of the melanocytes in the epidermis area is an important step. However, the detection of the melanocytes from the epidermis area is difficult because other keratinocytes that are very similar to the melanocytes are also present. This paper proposes a novel computer-aided technique for detection of the melanocytes in the epidermis area of skin histopathological images. An adaptive threshold technique is first applied to segment all the keratinocytes in the image. In order to distinguish the melanocytes from other keratinocytes, a novel technique based on radial line scanning is proposed to estimate the halo region of the melanocytes. Based on the estimated halo region of all the nuclei, an area ratio of estimated halo region and the nuclei is used to detect the melanocytes from all the keratinocytes. Experimental results on 40 different histopathological images of skin tissue containing 341 melanocytes show that the proposed technique provides a superior performance. Highlights? The first computerized technique for melanocytes detection in the skin histology. ? A novel radial line scanning algorithm to estimate halo region of melanocytes. ? Not sensitive to the inter- and intra-image variations. ? Shows superior performance compared to an alternative technique.

Cutaneous squamous cell carcinoma in two pediatric lung transplant patients on prolonged voriconazole treatment

Oral voriconazole is commonly used for treatment and prophylaxis of invasive fungal disease post‐LTx. Development of cutaneous SCC has been described in adult LTx recipients, although it is extremely rare in children. We describe two Caucasian children who developed cutaneous SCC beyond three yr post‐LTx. Both developed severe photosensitivity, actinic keratosis and required curative surgical excision of the cutaneous SCC lesions. Neither patient developed metastatic lesions nor had allograft dysfunction as a result of the SCC or the change in medical treatments. The effect of voriconazole on the development of malignant skin lesions is discussed and a recommendation on dermatologic surveillance, preventive measures against phototoxicity and early treatment of SCC are provided.

A Clinicopathologic Review of a Case Series of Dermatofibrosarcoma Protuberans with Fibrosarcomatous Differentiation

Background: Dermatofibrosarcoma protuberans with fibrosarcomatous differentiation (DFSP-FS) is a rare variant of DFSP with a more aggressive clinical course, characterized by higher rates of local recurrence, metastasis, and death. Methods: We conducted a clinicopathologic review of all DFSP-FS cases that occurred in Alberta, Canada, from 1997 to 2007. Results: Of the 75 DFSP cases reviewed, 4 demonstrated fibrosarcomatous differentiation. Three patients were female and one was male, and the age range was 25 to 76 years. Three tumors invaded to skeletal muscle, whereas one invaded to subcutaneous tissue only. Although perineural invasion was noted in all four cases, none exhibited lymphovascular space invasion. One local recurrence developed, and two of four tumors metastasized. Metastasis was associated with tumor size, tumor necrosis, grenz zone involvement, ulceration, thickness, and tumor grade. One patient died within 5 years of diagnosis. Conclusion: DFSP-FS represents a more aggressive subtype of DFSP. Several features of DFSP-FS may impart a higher risk of metastasis.

Pyoderma gangrenosum associated with alitretinoin therapy

Pyoderma gangrenosum (PG) is an uncommon ulcerative cutaneous condition, the etiology of which is poorly understood but is thought to be related to improper neutrophil function and chemotaxis. PG is a clinical diagnosis that requires exclusion of other ulcerative and inflammatory cutaneous disorders. A rare side effect of isotretinoin is the development of PG. We report the first case, to our knowledge, of PG associated with alitretinoin therapy (Appendix).

Eruptive melanocytic nevi induced by interferon for nodal metastatic melanoma: case report and review of the literature.

Background: The rapid appearance of multiple new melanocytic nevi is known as eruptive nevi and has been well documented to occur with certain medications, in particular chemotherapeutic agents. Methods: We report a case of a woman with melanoma complicated by nodal metastasis who developed multiple melanocytic nevi while on high-dose interferon. Results: Serial photographs confirmed that the pigmented lesions were of new onset, whereas histology documented that the lesions were dysplastic nevi. A survey of the literature documented numerous causes of eruptive nevi, which we review. To date, interferon has not been linked to eruptive nevi. Conclusions: The phenomenon of eruptive nevi has been attributed to medications, bullous dermatoses, immunosuppression, and systemic conditions and is possibly a paraneoplastic disorder. Interferon appears to be another possible cause of this disorder.

Erythema induratum: case series illustrating the utility of the interferon-γ release assay in determining the association with tuberculosis.

Background: The interferon-γ release assay (IGRA) is a novel method for detecting previous sensitization to tuberculosis (TB). Despite having several advantages over the tuberculin skin test (TST), including higher specificity and no influence from past bacille Calmette-Guérin (BCG) exposure, there are a limited number of reports describing its application in patients with erythema induratum (EI)/nodular vasculitis (NV), which is usually but not always related to TB. Objectives: The aim of our case series was to evaluate the usefulness of the IGRA for determining a TB association in patients with EI/NV. Methods: Retrospective chart reviews were conducted on four patients diagnosed with EI/NV at our institution in whom an IGRA had been performed. Results: All four subjects had positive TST results. The IGRA was also positive and therefore supported a link with TB in two cases. One patient responded completely to anti-TB therapy, whereas the second was lost to follow-up. Both cases unrelated to TB, by virtue of negative IGRAs, demonstrated complete response to immunosuppressive therapy (methotrexate), with one individual having failed anti-TB therapy first. Conclusion: Our case series highlights the utility of the IGRA for establishing a TB association in patients with EI/NV. Although limited by a small sample size, we propose adjunctive use of this test at the time of EI/NV diagnosis, especially in the setting of previous BCG exposure, so that management can be tailored according to whether an underlying relationship with TB exists.

Clinical and Dermoscopic Features of Pigmented Disseminated Superficial Actinic Porokeratosis: Case Report and Literature Review

Introduction: Porokeratosis is a benign hyperkeratotic skin tumour due to a clonal proliferation of keratinocytes and is characterised by a telltale annular threadlike configuration along the border of a skin-colored to erythematous papule that can expand centrifugally. Case Presentation: We are presenting a clinical and dermoscopic case of pigmented disseminated superficial actinic porokeratosis (DSAP) limited to the upper trunk of a white man with sun-damaged skin. Literature Review and Conclusion: A thorough review of PubMed failed to identify any previous reports on the dermoscopic appearance of pigmented porokeratosis. On dermoscopy, the presence of black dots limited to the periphery of the lesions is due to pigment incontinence and melanophages within the superficial papillary dermis limited to the area below the cornoid lamella. Pigmented DSAP is a unique morphological presentation of porokeratosis, and it is essential to be familiar with its clinical and dermoscopic presentation.

IgA Cutaneous Purpura Post–Renal Transplantation in a Patient With Long-Standing IgA Nephropathy Case Report and Literature Review

Background: IgA vasculitis is a small-vessel vasculitis caused by deposition of IgA antibodies in tissues. IgA nephropathy and IgAV have long been considered related conditions. Objective: To assess the prevalence and implications of new-onset Henoch-Schönlein purpura (HSP) after renal transplant in patients with underlying IgA nephropathy. Methods: The PubMed database was searched for keywords such as IgAV, IgA vasculitis, Henoch-Schönlein purpura, HSP, IgA nephropathy, and renal transplant. Results: Two cases of new-onset IgA vasculitis post–renal transplant after stopping the prednisone or receiving seasonal influenza vaccine have been reported. We report the case of new-onset IgA cutaneous vasculitis in a renal transplant patient with IgA nephropathy after reduction in his prednisone dosage. Conclusion: The new development of cutaneous IgA vasculitis is unusual in renal transplant patients with IgA nephropathy. Despite these patients’ being immunosuppressed, the presence of IgA vasculitis could signal the recurrence of IgA nephropathy.

Primary Systemic (Amyloid Light-Chain) Amyloidosis Masquerading as Pseudoxanthoma Elasticum Recognizing a Novel Clinicopathological Pattern

IMPORTANCE Primary systemic (amyloid light-chain [AL]) amyloidosis has a variety of cutaneous manifestations. In this case, we present a novel clinicopathological pattern of AL amyloidosis. OBSERVATIONS A woman in her 50s with a history of AL amyloidosis manifesting as macroglossia and bilateral carpal tunnel syndrome presented with skin-colored to yellow cobblestoned plaques to the neck and bilateral antecubital fossa. Although clinical similar to pseudoxanthoma elasticum (PXE), the skin changes were found to be due to amyloid deposition primarily around the pilosebaceous unit but also within the papillary and reticular dermis. Previous reports of PXE-like plaques in AL amyloidosis have been reported as part of a very rare entity termed amyloid elastosis. However, our case demonstrates several important clinical and pathological differences from this entity. Most notably, there was no dermal elastic fiber involvement, limited cutaneous and systemic involvement, and a fairly indolent course with better response to treatment. CONCLUSIONS AND RELEVANCE Identification of this atypical presentation of AL amyloidosis has important implications for early detection and rapid treatment. The lack of elastic fiber involvement establishes the uniqueness of this case, and further study may be required to determine if this histological finding has prognostic significance.