Dermatopathologic features of cutaneous squamous cell carcinoma and actinic keratosis: Consensus criteria and proposed reporting guidelines.

BACKGROUND: There is considerable variation in the literature regarding the dermatopathologic diagnostic features of and reporting guidelines for actinic keratosis (AK) and cutaneous squamous cell carcinoma (cSCC). OBJECTIVE: To develop consensus recommendations regarding diagnostic criteria, nomenclature, and reporting of AK and cSCC. METHODS: Literature review and cross-sectional multiround Delphi process including an international group of expert dermatopathologists followed by a consensus meeting. RESULTS: Consensus was achieved regarding the key dermatopathologic features necessary for diagnosing cSCC, AK, and associated variants; grading of degree of cellular differentiation in cSCC; utility of immunohistochemistry for diagnosis of cSCC; and pathologic features that should be reported for cSCC and AK. LIMITATIONS: Consensus was not achieved on all questions considered. CONCLUSION: Despite the lack of clarity in the literature, there is consensus among expert dermatopathologists regarding diagnostic criteria and appropriate reporting of AK and cSCC. Widespread implementation of these consensus recommendations may improve communication between dermatopathologists and clinicians, facilitating appropriate treatment of AK and cSCC.

Acute iododerma presenting as cryptococcoid neutrophilic dermatosis: A clinicopathological pitfall and interesting findings gleaned from a review of the literature.

Iododerma is an uncommon dermatosis caused by excessive iodine exposure and is associated with significant morbidity and mortality. Because of its heterogenous clinical presentation and variable histopathological findings, which depend on the time the skin biopsy is performed, the diagnosis of iododerma is often delayed. We report a rare case of acute iododerma in a woman with end-stage diabetic nephropathy with antecedent radioiodine contrast exposure, presenting histopathologically as cryptococcoid neutrophilic dermatosis (CND). We underscore important clinicopathological pitfalls to avoid misdiagnosis with similar overlapping entities such as Sweet syndrome, review all published cases of CND and draw novel insights into its associated entities.

Cryocrystalglobulinemia-An Uncommon Cutaneous Presentation of Multiple Myeloma and Novel Finding of Transepidermal Elimination of Crystals.

ABSTRACT: Cryocrystalglobulinemia (CCG) is a rare subset of type 1 cryoglobulinemia that is classically associated with an underlying paraproteinemia. The cryocrystalglobulins are characterized by extracellular crystals, which are eosinophilic, periodic acid-Schiff positive, and exhibit nonbirefringence under polarized light. This archetypal appearance renders CCG readily diagnosable histologically. Unlike in mixed cryoglobulinemias (types II and III cryoglobulinemia) where there is complement-mediated inflammation amounting to vasculitis, the deposition of crystallized paraproteins within vessels in CCG result in an occlusive vasculopathy and culminate in severe systemic involvement. Aside from cutaneous lesions, the resultant ischemic hypoperfusion manifest frequently with fulminant acute kidney failure, polyarthralgia, peripheral neuropathy, or gastrointestinal ulceration, conferring a poor prognosis. We present an unusual case of a patient diagnosed with immunoglobulin G kappa multiple myeloma that first presented with cutaneous necrosis as a result of CCG and did not have any renal impairment or fatal outcome. We highlight this uncommon entity to underscore the clinical importance of early diagnosis to avoid significant morbidity and mortality. In addition, we also discuss a novel feature of transepidermal elimination of crystalline precipitates demonstrated on his skin biopsy.

Fibroblastic Rheumatism Versus Variant Disease of Multinucleate Cell Angiohistiocytoma.

We report an unusual case of a 49-year-old woman who presented with persistent papulonodules over bilateral fingers and inframammary region in conjunction with features of connective tissue disease including symmetrical polyarthritis and Raynaud phenomenon. Skin biopsy showed an upper-to-mid dermal proliferation of bland spindled cells with thickened collagen bundles and occasional multinucleated giant cells. Dermal blood vessels were only marginally increased. On immunohistochemistry, both the spindled cells and multinucleated giant cells stained negatively for smooth muscle actin. Some of the spindled cells stained positively with CD68 and CD163, whereas the multinucleated giant cells stained negatively for both stains. Elastic fibers were absent on elastic Van Gieson. The clinical and histopathologic features raise a diagnostic dilemma between fibroblastic rheumatism and multinucleate cell angiohistiocytoma. The patient responded well to cyclosporine and methotrexate therapy, with gradual improvement of the finger nodules.

Noninvasive real-time characterization of non-melanoma skin cancers with handheld optoacoustic probes.

Currently, imaging technologies that enable dermsurgeons to visualize non-melanoma skin cancers (NMSC) in vivo preoperatively are lacking, resulting in excessive or incomplete removal. Multispectral optoacoustic tomography (MSOT) is a volumetric imaging tool to differentiate tissue chromophores and exogenous contrast agents, based on differences in their spectral signatures and used for high-resolution imaging of functional and molecular contrast at centimeter scale depth. We performed MSOT imaging with two- and three-dimensional handheld scanners on 21 Asian patients with NMSC. The tumors and their oxygenation parameters could be distinguished from normal skin endogenously. The lesion dimensions and depths were extracted from the spectral melanin component with three-dimensional spatial resolution up to 80 µm. The intraclass correlation coefficient correlating tumor dimension measurements between MSOT and ex vivo histology of excised tumors, showed good correlation. Real-time 3D imaging was found to provide information on lesion morphology and its underlying neovasculature, indicators of the tumor's aggressiveness.

Subungual Squamous Cell Carcinoma: The Diagnostic Challenge and Clinical Pearls.

Subungual squamous cell carcinoma is a rare entity and difficult to diagnose as its clinical presentation may resemble benign conditions. This case report highlights the need to maintain a high clinical index of suspicion, and recommends a practical approach for subungual conditions. Dermoscopy and a biopsy for histology are important adjuncts to clinch the diagnosis.

Epidermolysis bullosa pruriginosa: a case with a novel mutation and co-existent lichen amyloidosus.

Epidermolysis bullosa pruriginosa is a rare variant of dystrophic epidermolysis bullosa characterized by severely pruritic and cicatricial lesions localized to the extensor extremities. We report a Singaporean Chinese male with epidermolysis bullosa pruriginosa with an underlying novel mutation in the COL7A1 gene. A heterozygous acceptor splice site mutation IVS67-1G>T probably led to in-frame skipping of exon 68 (36-basepairs), resulting in a loss of 12 amino acids. Among his three children, only the youngest son, who had bilateral big toenail thickening, possessed the same mutation. His skin biopsy one decade ago revealed association of focal amyloidosis; a recent skin biopsy showed more established features of lichen amyloidosis. It is debatable whether the cutaneous amyloidosis was a secondary or primary phenomenon. Our report highlights that the diagnosis of epidermolysis bullosa pruriginosa may be obscured when cutaneous amyloidosis is coexistent.

Exogenous ochronosis in a Chinese patient: use of dermoscopy aids early diagnosis and selection of biopsy site.

The diagnosis of exogenous ochronosis is often challenging and requires a high index of suspicion. Herein, we report a case of exogenous ochronosis in a Chinese patient. The condition was caused by the use of bleaching agents, including creams containing hydroquinone. We demonstrate the use of dermoscopy as an invaluable tool for the early recognition of the condition, as well as in the selection of an appropriate site for a skin biopsy.

A rare combination of sebaceoma with carcinomatous change (sebaceous carcinoma), trichoblastoma, and poroma arising from a nevus sebaceus.

We report a case of a 48-year-old Malay female who presented with multiple tumors arising from a large nevus sebaceus on her right parieto-temporal scalp. Histologically, the tumors corresponded to a sebaceoma with carcinomatous change, a poroma and a trichoblastoma. Immunohistochemical staining of the sebaceous tumor with p53 showed strong within the areas of carcinomatous change, while there was negative to weak staining within the sebaceoma-like areas. A discussion on the potential secondary neoplasms from a nevus sebaceus ensues, with a review of this literature on multiple tumors from a nevus sebaceus.

Systematized epidermal nevus with epidermolytic hyperkeratosis improving with topical calcipotriol/betametasone dipropionate combination ointment.

We present the case of a 5-year-old boy who presented with systematized epidermal nevus with evidence of epidermolytic hyperkeratosis on skin biopsy. He was otherwise well, with normal growth and development and no evidence of other organ system involvement. He had experienced only mild improvement with potent topical corticosteroids. He reported more-marked improvement after 2 months of topical calcipotriol/betamethasone dipropionate combination ointment once a day to the lesions. Extensive epidermal nevi can lead to severe cosmetic disfigurement. We recommend a trial of topical calcipotriol/betamethasone dipropionate ointment for patients with extensive epidermal nevus not amenable to surgical treatment.

Congenital combined melanocytic nevus of the scalp with associated alopecia areata.

We report a case of a 20-year-old Chinese man with an alopecic congenital combined compound and blue melanocytic nevus of the scalp, associated with alopecia areata. The diagnosis of a combined melanocytic nevus was confirmed by histopathological examination and immunohistochemical stains, with exclusion of neurocristic hamartoma, which can have a similar clinical and histopathological appearance but different prognosis. In addition, we explore the association of this large melanocytic lesion with alopecia areata.

Is propionibacterium acnes associated with hair casts and alopecia?

We report a series of four patients who presented with complaints of diffuse non-scarring alopecia. They had similar clinical features of alopecia, hyperseborrhea, and distinct keratinaceous hair casts that encircled the hair shafts. Propionibacterium acnes was isolated from two of the patients' scalp, and Gram-positive, Giemsa-positive bacteria were seen in the hair follicles in the scalp biopsy of one of the patients. The patients' symptoms did not respond to standard treatment for seborrheic dermatitis, but responded to a course of systemic antibiotics targeting P. acnes. We propose a role for P. acnes colonization of the terminal hair follicles in the pathogenesis of hair casts, and possibly diffuse non-scarring alopecia. Possible mechanisms of pathogenesis are discussed with a literature review.

Lymphocytic thrombophilic arteritis: a newly described medium-sized vessel arteritis of the skin.

BACKGROUND: We encountered a distinct arteriolar histopathologic finding of lymphocytic vasculitis associated with a hyalinized fibrin ring in vessel lumina. Identical histologic findings have previously been described as macular arteritis. OBSERVATIONS: We describe 5 women (mean age, 25 years; age range, 20-34 years) with persistent, slowly progressive, patchy and reticular hyperpigmentation associated with livedo racemosa affecting predominantly the lower limbs. In the biopsy samples, infiltration of muscular vessel wall by inflammatory cells, affecting small arteries of the dermosubcutaneous junction or superficial subcutis, was present. Of the infiltrate, 90% or more consisted of mononuclear cells, mainly lymphocytes with an admixture of histiocytes. Neutrophils and eosinophils were absent or scant. Inflammation was confined to the vicinity of the vessel and the immediate surrounding panniculus. A concentric fibrin ring involving the entire periphery of the lumina of affected vessels was present in all the patients. Laboratory investigation results revealed that 4 patients had antiphospholipid antibodies in their serum. One of these patients had a heterozygous mutation of the factor V Leiden gene. Conclusion We term this arteritis lymphocytic thrombophilic arteritis to reflect the histologic features that combine lymphocytic vascular inflammation with changes representing a thrombophilic endovasculitis.