The utilization of spitz-related nomenclature in the histological interpretation of cutaneous melanocytic lesions by practicing pathologists: results from the M-Path study.
BACKGROUND
Spitz nevi, atypical Spitz tumors and spitzoid melanomas ('spitzoid lesions') represent controversial and poorly understood cutaneous melanocytic lesions that are difficult to diagnose histologically. It is unknown how these terms are used by pathologists.


METHODS
We describe use of Spitz-related terminology using data from the Melanoma Pathology (M-Path) study database comprising pathologists' interpretations of biopsy slides, a nation-wide study evaluating practicing US pathologists' (N = 187) diagnoses of melanocytic lesions (8976 independent diagnostic assessments on 240 total test cases, with 1 slide per case).


RESULTS
Most pathologists (90%) used the Spitz-related terminology. However, significant variation exists in which specific lesions were diagnosed as spitzoid and in the corresponding treatment recommendations. Recommendations ranged from 'no further treatment' to 'wide excision of 10 mm or greater' with no category capturing more than 50% of responses. For spitzoid melanoma diagnoses, 90% of pathologists recommended excision with ≥10 mm margin. Pathologists report less confidence in diagnosing these lesions compared with other melanocytic proliferations and are more likely to request second opinions and additional clinical information (all p < 0.05).


CONCLUSIONS
Spitzoid lesions are often not classified in any standardized way, evoke uncertainty in diagnosis by pathologists, and elicit variability in treatment recommendations.
Division of Dermatology, Department of Medicine, University of Washington, Seattle, WA, USA.
Ge
G
Zhao
Department of Dermatology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
Kachiu C
KC
Lee
Department of Medicine, University of Washington School of Medicine, Seattle, WA, USA.
Sue
S
Peacock
Department of Medicine, University of Washington School of Medicine, Seattle, WA, USA.
Lisa M
LM
Reisch
Pathology Associates, Clovis, CA, USA.
Stevan R
SR
Knezevich
Department of Pathology and Laboratory Medicine, Hospital of the University of Pennsylvania, Philadelphia, PA, USA.
David E
DE
Elder
Division of Dermatology, Department of Medicine, University of Washington School of Medicine, Seattle, WA, USA.|Dermatopathology Northwest, Bellevue, WA, USA.
Michael W
MW
Piepkorn
Department of Medicine, University of Washington School of Medicine, Seattle, WA, USA.
Joann G
JG
Elmore
Department of Pathology, Institut Curie, and Faculty of Medicine, University of Paris Descartes, Paris, France.
Raymond L
RL
Barnhill
D003880:Dermatology / Q000592:standards*; D006801:Humans; D008545:Melanoma / Q000145:classification* / Q000175:diagnosis; D018332:Nevus, Epithelioid and Spindle Cell / Q000145:classification* / Q000175:diagnosis; D000072142:Pathologists / Q000592:standards*; D010338:Pathology, Clinical / Q000592:standards*; D012878:Skin Neoplasms / Q000145:classification* / Q000175:diagnosis; D009626:Terminology as Topic
Spitz; dermatopathology; melanocytic nevus; melanoma; terminology
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