Chondroid Syringoma/Cutaneous Mixed Tumor Low Magnification Low magnification shows a well-circumscribed tumor composed of epithelial islands with easily identifiable glandular/ductal structures embedded in a myxoid and hyaline stroma.
TERMINOLOGY
Abbreviations
• Cutaneous mixed tumor (CMT)
Synonyms
• Apocrine mixed tumor
• Eccrine mixed tumor
• Mixed tumor of folliculosebaceous-apocrine complex
Definitions
• Well-circumscribed benign epithelial tumor with chondromyxoid matrix
CLINICAL ISSUES
Epidemiology
• Incidence
Rare
• Age
Middle-aged to elderly
• Sex
Male predominance
• Ethnicity
No ethnic predilection
Site
• Head and neck sites are most common
• Extremities and trunk
Presentation
• Skin-colored, asymptomatic, dermal to subcutaneous tumors
Natural History
• Slow growth
Treatment
• Surgical excision
Prognosis
• Excellent
Very rare malignant transformation
MACROSCOPIC
Size
• 0.5-3.0 cm
Sections to Be Submitted
• Representative sections of grossly different-appearing areas should be submitted
MICROSCOPIC
Histologic Features
• Well-circumscribed dermal to subcutaneous tumor
• Composed of proliferation of epithelial cells embedded in myxoid, chondroid, or fibrous stroma
• Apocrine ducts within tumor can be seen
Many authors consider CMT to be predominately tumor of apocrine origin
• Differentiation toward different parts of folliculosebaceous-apocrine complex reported
Focal areas of matrical or sebaceous differentiation may rarely be seen
• Eccrine differentiation may be present in some cases
• Large amounts of adipose tissue are seen in what are called lipomatous mixed tumors
• Calcification and ossification are rare focal findings
• Due to shrinkage of stroma, fibroblasts and epithelial cells within stroma are surrounded by halos and appear similar to cells of cartilage
• Epithelial component
Epithelial cells can be arranged singly, in small and large clusters, or in solid cords
Ductal structures are of variable size and shape
CMTs have been divided into 2 types according to ductal structures by some
– Tumors with tubular, branching lumina
– Tumors with small, tubular lumina
Cystic dilation and branching of ducts is common
PAS(+), amorphous, eosinophilic material (collagenous spherulosis) can be seen in tubular lumina
Larger ducts lined by 2 layers of cuboidal cells and peripheral layer of myoepithelial cells
Some CMT composed predominantly of small ducts and small epithelial clusters
Small ducts lined by single layer of cuboidal cells
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