Impact of clinical photographs on the accuracy and confidence in the histopathological diagnosis of mycosis fungoides.

BACKGROUND: The histopathological diagnosis of MF is challenging, and there is significant overlap with benign inflammatory processes. Clinical features may be relevant in the assessment of skin biopsies. METHODS: We provided photomicrographs to board-certified dermatopathologists and one hematopathologist with and without accompanying clinical photographs and assessed accuracy and confidence in diagnosing MF. RESULTS: We found that access to clinical photographs improved diagnostic accuracy in both MF and non-MF (distractors); the degree of improvement was significantly higher in the non-MF/distractor category. Across all categories, diagnostic confidence level was higher when clinical images were available. CONCLUSION: These findings suggest that clinical images are useful in making an accurate diagnosis of MF, and may be particularly helpful in ruling it out when an inflammatory disorder is clinically suspected.

A genomic survey of sarcomas on sun-exposed skin reveals distinctive candidate drivers and potentially targetable mutations.

Sarcomas on photodamaged skin vary in prognosis and management, but can display overlapping microscopic and immunophenotypic features. Improved understanding of molecular alterations in these tumors may provide diagnostic and therapeutic insights. We characterized 111 cutaneous sarcomatoid malignancies and their counterparts, including primary cutaneous angiosarcoma (n = 7), atypical fibroxanthoma (AFX) (n = 21), pleomorphic dermal sarcoma (PDS) (n = 17), extracutaneous undifferentiated pleomorphic sarcoma (n = 8), cutaneous leiomyosarcoma (LMS) (n = 5), extracutaneous LMS (n = 9), sarcomatoid squamous cell carcinoma (spindle cell squamous cell carcinoma) (S-SCC) (n = 24), and conventional cutaneous squamous cell carcinoma (SCC) (n = 20), by next-generation sequencing (NGS) using the StrataNGS panel for copy number variations, mutations, and/or fusions in more than 60 cancer-related genes. TP53 mutations were highly recurrent in most groups. Angiosarcoma displayed previously reported MYC amplifications, as well as CCND1 gains. RB1 mutations were relatively restricted to cutaneous LMS. As previously reported, PIK3CA mutations occurred in AFX, whereas RAS activation was more frequent in PDS. CDKN2A mutations were recurrent in AFX and S-SCC, whereas PDS displayed frequent CDKN2A deletion. S-SCC displayed mutational similarity to conventional SCC. BRCA1/2 mutations were specific to tumors with disease progression. In a subset, we detected potential driver events novel to these tumor types: activating mutations in IDH2 (PDS), MAP2K1 (angiosarcoma, PDS), and JAK1 (S-SCC) and copy gains in FGFR1 (angiosarcoma, S-SCC), KIT (AFX), MET (PDS), and PDGFRA (PDS). Our findings confirm and expand the spectrum of known genomic aberrations, including potential targetable drivers, in cutaneous sarcomatoid malignancies. In addition, certain events are relatively specific to particular tumors within this differential diagnosis and hence might be diagnostically informative.

Utility of Skin Biopsy and Culture in the Diagnosis and Classification of Chronic Ulcers: A Single-Institution, Retrospective Study.

In the United States, chronic ulcers affect 6.5 million people, with a cost of ≈$20 million annually. The most common etiology of chronic ulcers in the United States is venous stasis, followed by arterial insufficiency and neuropathic ulcers. Less common causes of chronic ulcers include infection, inflammatory etiologies such as vasculitis and pyoderma gangrenosum, and neoplastic causes. Obtaining skin biopsy and tissue culture can be helpful in diagnosing unusual causes of chronic ulcers; however, there are little data on the diagnostic utility of skin biopsy in rendering a definitive diagnosis of the etiology of chronic ulcers. A retrospective study of all skin ulcers biopsied during a 10-year period at the University of Washington was undertaken. Re-excisions and surgical wounds were excluded. A total of 270 ulcer biopsy specimens were included. In 48% of cases, no specific diagnosis could be rendered histologically. 44.8% of chronic ulcers biopsied were due to atypical causes, with neoplasms (basal cell carcinoma, squamous cell carcinoma, melanoma, and cutaneous T-cell lymphoma) being the most common. Vasculitis and pyoderma gangrenosum each represented 1.5% of rendered diagnoses. Concomitant skin culture was performed in 28.9% of cases, and special stains [acid-fast bacilli, Brown and Brenn (B&B), Grocott's methenamine silver, and periodic acid-Schiff stains] were performed in 34.0%. Although more than half (49 of 78) of tissue cultures were positive, only 6.8% (12 of 175) of special stains on tissue sections were positive. We conclude that although the etiology of many ulcers cannot be determined by routine histology alone, skin biopsy of ulcers remains a critical part of the workup given that when a specific cause can be determined, atypical etiologies, including neoplasms, represent a significant proportion of chronic ulcers. Limitations of our study include referral bias. Our results also confirm the higher diagnostic yield of conventional tissue culture compared with special tissue stain biopsies of skin ulcers.