Abstract:

The floating sign in dermatopathology has been defined as a collagen ball i.e., thick, homogenous, eosinophilic, circular/globular collagen fiber lined by histiocytes within an exaggerated pseudovascular cleft. It has been described in morphea, interstitial granulomatous dermatitis and, when surrounded by neoplastic T lymphocytes, interstitial granulomatous mycosis fungoides (free-floating sign). In this study, we propose the free sign (FS) as a nearly identical collagen fiber and cleft but lacking any cellular pseudorosette (histiocytes and/or lymphocytes) or requirement for a globular profile. Our observations suggest that FS may represent a sensitive and possibly specific feature of morphea and a general sign of early sclerosis that may be diagnostically helpful. We performed a case control study of 76 specimens, including 55 cases of morphea and 21 cases of other sclerosing disorders, including necrobiosis lipoidica (NL) and sclerodermoid graft versus host disease (SGVHD). We reviewed H&E-stained sections for FS as well as the floating sign and free-floating sign. FS was present in 83.6% (46/55) of the morphea cases, 42.8% (6/14) of NL and 28.5% (2/7) of SGVHD. The sensitivity and specificity of FS for morphea versus other disorders were 83% and 61%, respectively. The difference between groups was statistically significant (p=0.00002). The floating sign (including free-floating sign) was present in 9% (5/55) cases of morphea, 21.4% (3/14) cases of NL and 14.2% (1/7) cases of SGVHD. The diagnostic sensitivity of the floating sign in morphea was 9%, and specificity was 80% (p=0.25). FS appears to be a frequent and potentially diagnostically useful finding in view of its prevalence in morphea (sensitivity, 83%). We also suspect FS may represent a general clue to the presence of early or evolving sclerosis.

Financial Disclosure:
No current or relevant financial relationships exist.

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Maria Fernanda Ortega Springall, MD

Biography