Paraganglioma-like Dermal Melanocytic Tumor
David Cassarino, MD, PhD
Cyril Fisher, MD, DSc, FRCPath
Key Facts
Terminology
Paraganglioma-like dermal melanocytic tumor (PLDMT)
Rare dermal-based, low-grade melanocytic tumor with histologic similarities to paraganglioma
Microscopic Pathology
Typically composed of packets of oval to spindle-shaped cells surrounded by thin fibrous septa
Uniform nuclei, small nucleoli, clear cytoplasm
Ancillary Tests
Positive for S100; MART-1/Melan-A, and HMB-45 (variable)
Top Differential Diagnoses
Clear cell/balloon cell melanoma
Clear cell sarcoma
Perivascular epithelioid cell tumor (PEComa)
Primary dermal melanoma
 Histologic sections show a diffuse proliferation of clear cells located in the dermis. PLDMT is often a well-circumscribed, but unencapsulated, dermal-based tumor that can extend into the subcutis. |
 High magnification shows that the tumor is composed of closely packed nests of cells with clear or granular cytoplasm and round to oval nuclei with small nucleoli  . |
TERMINOLOGY
Abbreviations
Paraganglioma-like dermal melanocytic tumor (PLDMT)
Definitions
Dermal-based low-grade melanocytic tumor with histologic similarities to paraganglioma
CLINICAL ISSUES
Epidemiology
Incidence
Very rare tumors; only 10 cases reported to date
Age
Typically occur in young adults
Range: 18-53 years
Mean: 35 years
Gender
More common in females
Site
Usually occur on extremities
Mostly lower limb
Thigh, knee, lower leg
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