Pemetrexed-Induced Pseudocellulitis: A Diagnostic Conundrum.

Pemetrexed, an anti-folate, antineoplastic agent, effectively treats various malignancies such as non-small cell lung cancer (NSCLC) and mesothelioma. Here, we report two cases of recurrent pemetrexed-induced lower extremity erythema and edema, one in a 60-year-old male and the other in a 47-year-old male, who were both treated for recurrent cellulitis on multiple occasions before finally being diagnosed with pemetrexed-induced pseudocellulitis (PIP), a rarely reported adverse effect. This is an important diagnostic pitfall for clinicians to be aware of, as early recognition may minimize patient morbidity and prevent unnecessary hospitalization and antibiotic use for presumed cellulitis.

Real world validation of an adjunctive gene expression-profiling assay for melanoma diagnosis and correlation with clinical outcomes at an academic center.

A commercially available diagnostic gene expression profiling (GEP) assay (MyPath™) reportedly has high sensitivity and specificity in distinguishing nevi from melanoma based on manufacturer-conducted studies. However, data regarding the performance of this GEP assay in routine clinical practice are lacking. The purpose of this study was to better assess the real-world performance of GEP in a large academic practice. Retrospective review of GEP scores were compared with final histomorphologic interpretation on a wide spectrum of melanocytic lesions demonstrating some degree of atypia. In a sample of 369 lesions, the sensitivity (76.1%) and specificity (83.9%) of the GEP test as compared with final dermatopathologist-rendered diagnosis in our dataset was appreciably lower than that reported in the prior manufacturer-conducted validation studies. Limitations of this study were that it was a single-center study, its retrospective nature, nonblinded nature of GEP test result, concordance of only two pathologists, and limited follow-up time.The sensitivity and specificity of a commercially available GEP diagnostic assay for melanoma may be lower in routine clinical practice, where melanocytic lesions typically exhibit some degree of histomorphologic atypia. Reported cost effectiveness of GEP testing is questionable if all ambiguous lesions that undergo such testing are re-excised in clinical practice.

A retrospective review of 93 cases of cellular dermatofibromas.

BACKGROUND: Cellular dermatofibromas (CDF) are an uncommon variant of benign fibrous histiocytomas with propensity to recur and rarely metastasize as well as demonstrate histologic similarities to more dangerous lesions. OBJECTIVES: The aim of this present study was to further describe the presentation and outcome of the cellular variant of benign fibrous histiocytomas so that it can be diagnosed and treated appropriately. METHODS: A retrospective chart review was performed on all patients seen in a single hospital system in Detroit, Michigan, from 2007 to 2017. CDF was confirmed by pathology. Baseline demographics, specialty service of diagnosis and treatment, treatment modality, and outcome were collected. RESULTS: Of the 93 qualifying patients, the average age at diagnosis was 42.65 years. The most common specialty service that diagnosed and treated patients was dermatology (38.71%). About 95.0% of CDF stained positive for Factor 13A (19/20), and 90.48% were CD34 negative (19/21). Of patients, 33.33% had recurrences of their CDF (9/27). Two patients had three or more recurrences. One patient's death was attributed to the CDF. CONCLUSION: CDF have a high local recurrence rate and similarities to more dangerous and malignant lesions. Patients with cellular dermatofibromas present to many subspecialty services for diagnosis and should be treated aggressively.

Lymphoplasmacytic Plaque in Children: A Demonstrative Case of an Emerging Clinicopathologic Entity.

Lymphoplasmacytic plaque in children is a rare but increasingly reported clinicopathologic entity characterized by extratruncal erythematous solitary plaques, most often in children and Caucasian girls, that are thought to be a reactive or pseudolymphomatous process. We report a demonstrative case of lymphoplasmacytic plaque in a 3-year-old girl and discuss the clinical and pathologic experience with this entity.

Vascular patterns in mature hypertrophic burn scars treated with fractional CO2 laser.

BACKGROUND AND OBJECTIVE: Fractional CO2 laser has recently emerged as a promising therapeutic modality to improve the texture and appearance of burn scars. An issue in many burn scars is persistent erythema, which traditionally has been treated with vascular lasers. Interestingly, fractional CO2 lasers have been shown to improve the appearance of burn scars, including erythema, but no mechanism has been proposed for this change. Our objective is to evaluate the histopathologic changes in vasculature in burn scars treated with fractionated CO2 laser, and to attempt to describe the mechanism behind reduced erythema following treatment. STUDY DESIGN/MATERIALS AND METHODS: Uncontrolled, prospective study of ten patients with mature burn scars, from a clinical and histological perspective. Biopsy specimens were obtained before and 2 months after 3 treatment sessions. Anti-CD31 immunostaining was performed to highlight vascular patterns in biopsy specimens. RESULTS: In histological analysis, an increase in vascular density, particularly of small caliber vessels, was seen following treatment, with an 82.6% average increase in vasculature (P = 0.028). This increase in vascularity correlated with a decrease in clinical erythema and vascularity scores, measured using the Vancouver Scar Scale. CONCLUSION: Mature hypertrophic burn scars treated with a fractional CO2 laser showed a statistically significant increase in vascular density in the superficial dermis. A non-statistical decrease in clinically perceived erythema and improvement of overall appearance was seen. To our knowledge, this is the first report of increased vascular density in burn scars treated with fractional CO2 laser and suggests our prior assumptions on causes of erythema in mature hypertrophic scars may need to be challenged.

Evaluation of clinical results, histological architecture, and collagen expression following treatment of mature burn scars with a fractional carbon dioxide laser.

OBJECTIVE: To assess mature burn scars treated with a fractional carbon dioxide laser for changes in histological architecture, type I to III collagen ratios, density of elastic tissue, and subjective measures of clinical improvements. DESIGN: Uncontrolled, prospective study of patients with mature burn scars, from a clinical and histological perspective. Biopsy specimens were obtained before and 2 months after 3 treatment sessions. The tissue was prepared with Verhoff von Giesen (VVG) stain to discern elastic tissue and Herovici stain to differentiate types I and III collagen. SETTING: Subjects were recruited from the Grossman Burn Centers. PARTICIPANTS: Of 18 patients with mature burn scars, 10 completed the entire treatment protocol. INTERVENTION: Participants received 3 treatments with a fractional carbon dioxide laser. MAIN OUTCOME MEASURES: Vancouver Scar Scale and Patient and Observer Scar Assessment Scale survey scores. In histological analysis, imaging software was used to measure changes in collagen subtype and elastic tissue. A rating scale was developed to assess normal vs scar architecture. RESULTS: The first hypothesis that significant histological improvement would occur and the second hypothesis of a statistically significant increase in type III collagen expression or a decrease in type I collagen expression were confirmed. There were no significant changes in elastic tissue. Statistically significant improvements were seen in all survey data. CONCLUSIONS: Treatment with a fractional carbon dioxide laser improved the appearance of mature burn scars and resulted in a significant improvement in collagen architecture following treatment. Furthermore, in treated skin specimens, a collagen subtype (types I and III collagen) profile resembling that of nonwounded skin was found.

Manual microdissection technique in a case of subcutaneous panniculitis-like T-cell lymphoma: a case report and review.

Demonstration of T-cell receptor gene monoclonality often plays an important role in the diagnosis of T-cell lymphoma. When a test to detect monoclonality is performed on whole tissue sections, the presence of a reactive lymphocyte population may reduce sensitivity. This may be especially true for early or borderline cases of lymphoma. Microdissection techniques may be utilized to more readily identify a clonal population of lymphocytes. Subcutaneous panniculitis-like T-cell lymphoma represents a cutaneous lymphoid neoplasm whose clinical course may vary from an indolent, waxing and waning course to an aggressive course resulting in death. We report the first case of a microdissection technique used to facilitate diagnosing a case of subcutaneous panniculitis-like T-cell lympoma.

Mohs micrographic surgery for the treatment of cutaneous lymphadenoma.

Cutaneous lymphadenoma (CL) is a benign neoplasm commonly presenting on the head and neck of young and middle-aged adults. Complete surgical excision of CL is the treatment of choice and appears to be curative. As compared to local excision without margin control, Mohs micrographic surgery (MMS) may allow for more definitive tumor extirpation for large cases of CL and allow for greater tissue preservation at functionally and aesthetically sensitive sites. We present a case of cutaneous lymphadenoma presenting on the right cheek of a middle-aged male who was successfully treated with MMS.

Immunohistochemical staining of palisading basal cells in Bowen's disease and basal involvement in actinic keratosis: contrasting staining patterns suggest different cells of origin.

Actinic keratosis (AK) and Bowen's disease (BD) are common patterns of in situ squamous cell carcinoma of the epidermis. In AK, atypical keratinocytes proliferate in the lower portion of the epidermis including the basal layer. In contrast, BD features atypical squamous cells in all portions of the epidermis but initially leaves basal cells in palisades along the basement membrane. To characterize immunohistochemically keratocyte proliferation in AK and Palisading Basal Cells (PBC) in BD, we stained microarray samples of 45 AK and 25 BD with Molecular Immunology Borstel (MIB-1). Subsequent immunostaining of full mounted sections examined 11 BD, 7 AK, and 4 examples of psoriasis for MIB-1 (as a proliferative marker) and p53 (as a cell cycle regulatory marker). AK stained for MIB-1 and p53 antibodies only in lower portion of epidermis and included the basal layer. BD with typical PBCs stained positive for both markers throughout the epidermis, except for the basal layer. Psoriatic biopsies stained positively for the 2 markers only in the basal and parabasal layers. Normal epidermis adjacent to the lesions in AK and BD biopsies stained sparsely in the basal layers. The correlation of different histologic patterns of epidermal involvement with different immunohistochemical patterns of stains argues for different cells of origin for BD versus AK. Lack of expression of proliferative antigens in palisading basal cells in BD provides evidence that PBCs are not the cell of origin for BD. Conversely in AK, expression of MIB-1 and p53 in basal cells argues that these cells play a role in histogenesis of AK.

Syringolymphoid hyperplasia with alopecia: two case reports and review of the literature.

Syringolymphoid hyperplasia with alopecia is an uncommon, but histopathologically distinct, skin disorder that has been reported to occur with and possibly represent a syringotropic variant of cutaneous T-cell lymphoma. We report 2 patients with syringolymphoid hyperplasia with alopecia. Both had CD4-positive infiltrates; 1 also demonstrated loss of CD7. One patient had evidence of T-cell clonality by gene rearrangement studies, but neither had histologic evidence of cutaneous T-cell lymphoma. Because the natural progression of syringolymphoid hyperplasia with alopecia remains to be fully explained, close follow-up of patients is advised.

Solitary sclerotic fibroma of skin: a possible link with pleomorphic fibroma with immunophenotypic expression for O13 (CD99) and CD34.

BACKGROUND: Solitary sclerotic fibroma (SF) presents as a well circumscribed dermal nodule, composed of sparse spindle cells with alternating wavy collagen fibers arranged in a storiform pattern. The histogenesis and nature of this histologically distinct lesion are uncertain. Whether this peculiar tumor represents a true hamartoma or a degenerating end of various fibrous lesions such as pleomorphic fibroma (PF), dermatofibroma, or angiofibroma is still controversial. High proliferating index of spindle cells in SF argues against the possibility of being a degenerating end product of another lesion. METHODS: We studied morphological features and immunoprofile of eight SFs, in comparison with four PFs, one collagenized dermatofibroma, two angiofibromas, and two periungual fibromas. Immunostains for CD34, CD31, O13 (CD99), Factor XIIIa, S-100, CD68 (KP-1), and MIB-1 were carried out using a labeled streptavidin-biotin method with DAKO-automated immunostainer. Paraffin blocks of two SFs were reprocessed for electron microscopic studies. Clinical data of all patients with SF were also reviewed. RESULTS: Spindle cells and pleomorphic cells in SF and PF showed diffuse immunoreactivity for CD34 and O13 but were negative for CD31, S-100, and CD68. Spindle cells in one dermatofibroma and one angiofibroma were positive for Factor XIIIa. Proliferating index (MIB-1) was very low in all cases of SF, contradicting some previous reports. CONCLUSIONS: SF is a fibrotic lesion with cells positive for CD34 and O13. It shares a common immunoprofile with PF but is distinct from dermatofibroma and other common spindle cell lesions of skin. O13 expression in SF has not been previously described.

Polymorphous light eruption in African Americans: pinpoint papular variant.

BACKGROUND: Polymorphous light eruption (PMLE) is the most common chronic idiopathic photodermatosis usually manifesting as a papular eruption (3-6 mm), with several other morphological variants described. METHODS: Between June 1998 and August 2001, nine patients presented with complaints of a pruritic pinpoint papular eruption associated with sun exposure. A detailed history and complete skin examination were performed along with a skin biopsy if active lesions were present. Phototesting to ultraviolet-A (UV-A), ultraviolet-B (UV-B) and visible light was performed in four patients. Antinuclear antibody (ANA) testing was performed in three patients. The diagnosis of PMLE was made based on the history, morphology of the lesions, results of phototesting and skin biopsy if available. RESULTS: In all patients, pinpoint papules (1-2 mm) were observed on sun-exposed areas, sparring the face and flexural surfaces. All patients were African American women with skin type IV-VI and a mean age of 39.3 years (range 21-52 years). Phototest results were normal in three patients; one patient, who was on glyburide, had a decreased minimal erythema dose to UV-A. ANA testing was negative. Two histopathologic patterns were observed: (i) focal lichenoid and perivascular lymphohistiocytic infiltrate with red blood cell extravasation in four specimens and (ii) superficial and deep interstitial lymphocytic infiltrate with papillary dermal edema in the remaining three specimens. All patients responded to topical corticosteroids, broad-spectrum sunscreens and antihistamines. CONCLUSION: Recognition of this pinpoint papular variant of PMLE in dark-skinned individuals is important in the evaluation and management of these patients.