Table of Contents
Definition / general | Essential features | Terminology | Epidemiology | Sites | Etiology | Clinical features | Case reports | Clinical images | Gross description | Microscopic (histologic) description | Microscopic (histologic) images | Cytology description | Cytology images | Positive stains | Electron microscopy description | Differential diagnosis | Additional referencesCite this page: Riddle N, Hale C. Eccrine spiradenoma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/skintumornonmelanocyticeccrinespiradenoma.html. Accessed January 19th, 2021.
Definition / general
- Benign adnexal tumor with eccrine differentiation, may be derived from the secretory coil
- Extremely painful lesions, anywhere in body
- Rarely transforms to high grade malignancy
Essential features
- Solitary, painful, slowly growing, pink-gray lesion, often > 1cm
- Well circumscribed, round / oval cell nests ("blue balls") in dermis or subcutaneous tissue
- Small basaloid cells on the outside and larger polygonal cells with vesicular nuclei and prominent nucleoli towards the center
Terminology
- Also known as spiradenoma
Epidemiology
- Commonly during reproductive age
Sites
- Trunk > Scalp
- Genital area rare (vulva, clitoris, labia majora)
Etiology
- May be associated with CTNNB1 or CYLD gene mutations (Brooke-Speigler syndrome)
Clinical features
- Painful, slow growing mobile nodule. treated by excision
- Rarely linear, zosteriform or Blaschko line type configuration
- Excellent prognosis (benign lesion), unless malignant transformation
- Malignant transformation: rapid growth, ulceration, discoloration
Case reports
- 41 year old woman with malignant eccrine spiradenoma of vulva (Int J Gynecol Cancer 2006;16:1465)
- 67 year old woman with carcinosarcoma ex eccrine spiradenoma of vulva (Int J Gynecol Pathol 2011;30:301)
- 73 year old with facial lesion (Indian J Dermatol Venereol Leprol 2008;74:541)
Clinical images
Gross description
- Pink–gray or tan nodule, usually solitary
Gross description
- Painful, slow growing solitary nodule, head/neck, adults > children
- Occasional multiple lesions, linear or Blaschkoid distribution
Microscopic (histologic) description
- Well circumscribed, round-oval cell nests ("blue balls") in dermis or subcutaneous
- Closely packed basaloid cells in organoid arrangement – more polygonal in center
- Delicate fibrovascular capsule
- No epidermal connection
- May see ductal structures or squamoid areas
- Lymphocytes common throughout lesion
- Dilated intervening vessels may occur, sometimes so marked as to mimic vascular tumor
- Cystic degeneration may occur
- Malignant transformation: highly atypical cells, infiltrating, with numerous mitoses; sarcomatous features may be seen; often residual benign spiradenoma present
Microscopic (histologic) images
Cytology description
- Small cells with scant cytoplasm, hyperchromatic nuclei, no or minimal atypia, very rare mitoses
Electron microscopy description
- Epithelial and myoepithelial cells
Differential diagnosis
- Cylindroma: small islands of tumor cells with 'jigsaw puzzle' pattern; thick, eosinophilic, material around cell clusters
- Cutaneous lymphadenoma
- Metastatic carcinoma
- Synovial sarcoma
- Thymoma
Additional references