Faculty Bibliography

BACKGROUND:Dermatopathologists sometimes encounter patients with features of psoriasis vulgaris and additional changes of eczematous dermatoses. These cases are challenging to diagnose, and the clinical implications are unclear. In the age of targeted therapy, it is important to improve our understanding of these findings so that patients are managed appropriately. OBJECTIVE:To characterize the clinical characteristics, histopathological features, diagnostic workup, successful treatment, and outcomes of patients with overlapping histopathologic features of psoriasis vulgaris and eczema. METHODS:We conducted a retrospective chart review of 20 patients who had received the histopathologic diagnosis of psoriasis vulgaris with eczematous changes noted on skin biopsy. A database that included information about clinical characteristics, comorbidities, histopathological features, diagnostic workup, treatment modalities, and outcomes was created and analyzed. RESULTS:Twenty patients were included in this study, with an average age of 57.3 years. After clinicopathologic correlation, most patients were diagnosed with psoriasis (85%), and the remainder were determined to have an eczematous dermatitis. Thirty-five percent of patients were diagnosed with allergic contact dermatitis, either in combination with psoriasis (6 patients) or alone (1 patient). Topical glucocorticoids were the most common effective therapy used, and systemic therapies were required in nearly half of patients for successful treatment. CONCLUSION/CONCLUSIONS:This study offers insights into the clinically and histopathologically challenging diagnosis of psoriasis vulgaris with eczematous changes and offers the diagnostic term "eczematized psoriasis" to describe these patients. The presence of allergic contact dermatitis should be considered in these patients.

The cutaneous manifestations of cytomegalovirus (CMV) vary and may be difficult to identify histopathologically. Cutaneous CMV lesions are relatively rare and may be overlooked as infection usually presents in visceral organs, particularly the respiratory and gastrointestinal tract. Cutaneous manifestations of CMV infection are heterogeneous, with ulceration in the genital area occurring most commonly. This case highlights an unusual pustular presentation of CMV infection to aid in the recognition and diagnosis of cutaneous lesions. We report a 52-yearold male, with a history of chronic lymphocytic leukemia, who presented with multiple, generalized, tender, erythematous, draining papules and nodules in the skin. Histopathology revealed a dense, pustular infiltrate with characteristic cytomegalic inclusions in the deep dermis. This highlights the importance of considering CMV infection in the differential diagnosis of pustulonodular skin lesions, particularly in immunocompromised patients.

BACKGROUND:In instances of suspected cutaneous infection, standard of care includes obtaining skin biopsies for histology and tissue culture. Few studies have compared the clinical utility of each test. OBJECTIVE:To assess the concordance of results between tissue culture and histology, and clinicopathologic features that may influence the diagnostic yield of each test. METHODS:A retrospective review of all patients who underwent skin biopsy for histology and tissue culture at New York University from 2013-2018. RESULTS:Of 179 patients, 10% had positive concordance, 21% had positive tissue culture only, and 7% had positive histology only. We calculated a kappa correlation coefficient of 0.25 between histology and tissue culture [ref 0.21-0.39=minimal agreement]. Histology exhibited higher sensitivity in detecting fungi, whereas tissue culture was more sensitive in identifying gram-negative bacteria. Antimicrobial use prior to biopsy led to significantly fewer positive cultures (37.5% versus 71%; p=0.023) in patients ultimately diagnosed with infection. LIMITATIONS/CONCLUSIONS:This study was conducted at a single institution thereby restricting its broad applicability. The lack of a validated gold standard to diagnose infection also limits interpretation of results. CONCLUSION/CONCLUSIONS:Tissue culture and histopathology often yield discordant results. Dermatologists should recognize specific test limitations, yet high clinical utility in special circumstances, when approaching cases of suspected infection.