Spiradenoma
Eccrine spiradenoma (older — apocrine origin now favoured); painful tumour of the skin (one of the classical "ANGEL" / "BENGAL" mnemonics for painful skin tumours)
Spiradenoma is a benign adnexal tumour with apocrine differentiation that classically presents as a single, deep, blue-grey to violaceous, often painful dermal-subcutaneous nodule on the head, neck or upper trunk of a young to middle-aged adult. The pain is paroxysmal and disproportionate to the lesion's small size — placing it on classical mnemonics of "painful skin tumours" alongside leiomyoma, glomus tumour, neuroma and others. Multiple spiradenomas — particularly when associated with cylindromas and trichoepitheliomas — are pathognomonic of Brooke-Spiegler / CYLD cutaneous syndrome. Although themselves benign, long-standing spiradenomas carry a small but well-documented risk of malignant transformation to spiradenocarcinoma, signalled by abrupt growth, ulceration or dramatic increase in pain.
Clinical features
- Solitary firm blue-grey to violaceous dermal / subcutaneous nodule, typically 1–2 cm, often deeply situated.
- Distinctive feature — spontaneous and paroxysmal pain, often nocturnal, often worse with cold or pressure (similar to glomus tumour); pain can be the dominant presenting symptom.
- Distribution — head, neck, upper trunk; less often extremities.
- Median age 20–40; both sexes; sporadic onset.
- Multiple spiradenomas — characteristic of Brooke-Spiegler syndrome; co-exist with cylindromas and trichoepitheliomas.
- Painful skin tumour mnemonics — "ANGEL" (Angiolipoma, Neuroma, Glomus, Eccrine spiradenoma, Leiomyoma) or "BENGAL" (Blue rubber bleb, Eccrine spiradenoma, Neurilemmoma, Glomus, Angiolipoma, Leiomyoma).
Histology
- Well-circumscribed, deep dermal (sometimes subcutaneous) nodule consisting of large basophilic basaloid lobules — appearing "blue balls in the dermis" on low power.
- Two cell populations within each lobule:
- Outer small dark basaloid cells.
- Inner larger pale ductal cells.
- Hyaline droplets between cells; intracytoplasmic ducts.
- Prominent intratumoral lymphocytes.
- No atypia, mitoses or necrosis in benign spiradenoma.
- Histological overlap with cylindroma is common — combined "spiradenocylindroma" tumours frequent.
- Differential by histology: cylindroma (jigsaw pattern, hyaline rim around lobules); BCC (lacks dual cell population, no hyaline); apocrine carcinoma (atypia, mitoses).
Malignant transformation — spiradenocarcinoma
- Lifetime risk in solitary spiradenoma is very low.
- In Brooke-Spiegler syndrome, cumulative risk in any of the multiple lesions is estimated 5–10%.
- Warning signs:
- Abrupt growth in a previously stable nodule.
- Ulceration.
- Dramatic increase in pain.
- Bleeding.
- Fixity to deeper tissues.
- Any change should prompt biopsy — see spiradenocarcinoma.
Management
- Solitary symptomatic spiradenoma — surgical excision with histology; pain typically resolves immediately.
- Multiple lesions in Brooke-Spiegler syndrome:
- Staged excision of symptomatic lesions.
- Topical / systemic adjuncts (sirolimus, tropomyosin receptor kinase inhibitors) — emerging.
- Annual full-skin review.
- Genetic counselling and CYLD testing.
- Biopsy any changing lesion to exclude spiradenocarcinoma.
References
- Englander L et al. A novel painful skin lesion — eccrine spiradenoma. Cutis; 2008.
- Kazakov DV et al. Spiradenoma — clinicopathological review. Am J Dermatopathol; 2009.
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