Pure and Mixed Desmoplastic Melanomas: A Retrospective... : The American Journal of Dermatopathology (original) (raw)

Original Study

Pure and Mixed Desmoplastic Melanomas: A Retrospective Clinicopathologic Comparison of 33 Cases

Chu, Sherman BS*,†; Schrom, Kory P. MD‡; Tripathi, Raghav MPH*; Conic, Rosalynn R. Z. MD, PhD§; Ezaldein, Harib H. MD*,‡; Scott, Jeffrey F. MD*,‡,¶; Honda, Kord MD*,‡

*Department of Dermatology, Case Western Reserve University, Cleveland, OH;

†Western University of Health Sciences, College of Osteopathic Medicine of the Pacific, Northwest, Lebanon, OR;

‡Department of Dermatology, University Hospitals Cleveland Medical Center, Cleveland, OH;

§Department of Family and Preventive Medicine, University of California San Diego, San Diego, CA; and

¶Department of Dermatology, Johns Hopkins University, Baltimore, MD.

Correspondence: Sherman Chu, BS, Department of Dermatology, Case Western Reserve University, 2109 Adelbert Road, Cleveland, OH 44106 (e-mail: [email protected]).

S. Chu was funded by 5 T32 AR 7569-25. K. P. Schrom was supported by a fellowship grant from the National Psoriasis Foundation. R. Tripathi was supported by a grant from the Case Comprehensive Cancer Center. R. R. Z. Conic was funded by 5 T32 AR 7569-23.

The authors declare no conflicts of interest.

Abstract

Background:

Pure and mixed desmoplastic melanomas (DMs) may have different natural histories and behaviors.

Methods:

We conducted a retrospective review of patients diagnosed with DM at our institution between January 1997 and April 2019. A total of 33 unique DMs were identified and subsequently analyzed based on the histologic type (pure vs. mixed).

Results:

The majority (57.6%) of our cases were classified as pure histology. Patients with pure DMs were more likely to be men (P = 0.035) and be older than 65 years (P = 0.019) compared with patients with mixed DMs. Patients with mixed DM were more likely to have mitoses present (P = 0.001) compared with patients with pure DM. There were no differences in ulceration, perineural invasion, vascular invasion, or survival between patients with pure and mixed histologic subtypes. In addition, no differences in sentinel lymph node biopsy, radiation, or chemotherapy were noted between the 2 histologic subtypes. Immunohistochemistry showed that 27.3% of the pure DMs stained with Melan-A and HMB45 were positive for these immunomarkers.

Conclusions:

Pure and mixed variants of DM were found to have similar clinicopathologic characteristics. Patients with the mixed histologic subtype were more likely to have mitoses, but no difference in the therapeutic management or patient survival was seen between the 2 subtypes.