Spiradenocarcinoma
Malignant eccrine spiradenoma; spiradenocylindrocarcinoma (when arising in cylindro-spiradenoma)
Spiradenocarcinoma is the rare malignant counterpart of the benign eccrine spiradenoma — historically described as arising from malignant transformation of a long-standing benign spiradenoma; modern series increasingly recognise de novo spiradenocarcinoma without an antecedent benign component, characterised clinically by abrupt growth, ulceration, pain or change in a previously stable nodule that has often been present for decades. It may occur sporadically or in the context of Brooke-Spiegler syndrome (CYLD germline mutation, also predisposing to multiple cylindromas, spiradenomas and trichoepitheliomas). The clinical course can be aggressive, but metastatic behaviour is grade-dependent: regional nodal involvement is uncommon at presentation (reported up to ~15–17% over the disease course) and distant metastasis (lung, liver, bone) occurs in up to ~30% of high-grade tumours; reported 5-year overall survival is ~75% (SEER), lower for high-grade disease. Wide local excision plus regional nodal assessment is the standard of care.
Clinical features
- Long-standing (often 20–40-year) benign nodule that recently changes — sudden growth, ulceration, bleeding, pain or colour change.
- Trunk and extremities most common; head and neck in Brooke-Spiegler-related cases.
- Median age 60; F>M.
- May present as a solitary lesion or — in Brooke-Spiegler syndrome — as one of multiple cylindromas / spiradenomas / trichoepitheliomas, the so-called "turban tumour" appearance on the scalp.
- Family history of cylindromas / sweat-gland tumours raises suspicion for Brooke-Spiegler.
Histology
- Biphasic appearance: residual benign spiradenoma component (basophilic islands of small basaloid cells around hyaline droplets) plus an abrupt transition into a high-grade malignant component (sheets of pleomorphic cells, brisk mitoses, necrosis).
- The malignant component may be undifferentiated, squamous, sarcomatoid or adenocarcinomatous.
- Loss of the dual-cell-layer architecture characteristic of benign spiradenoma.
- Immunohistochemistry: variable; loss of myoepithelial markers in the malignant component.
- CYLD mutation testing (germline) if Brooke-Spiegler suspected.
Management
- Wide local excision with 1–2 cm margins; Mohs micrographic surgery for facial / scalp lesions.
- Sentinel lymph node biopsy strongly recommended.
- Imaging staging (CT or PET-CT).
- Adjuvant radiotherapy for incomplete margins, multiple positive nodes or extracapsular spread.
- Systemic therapy for metastatic disease — limited evidence; doxorubicin-based chemotherapy borrowed from soft-tissue sarcoma protocols; case reports of immune checkpoint inhibitor activity.
- Genetic counselling and CYLD testing if Brooke-Spiegler suspected — see syndrome page.
Prognosis
5-year overall survival ~75% (SEER), lower for high-grade disease. Adverse prognostic factors include high-grade transformation, large tumour size (>5 cm), positive nodes and distant metastasis. Long-term surveillance is essential — recurrence may occur years after initial treatment.
References
- Granter SR et al. Malignant eccrine spiradenoma — clinicopathologic study. Mod Pathol; 2000.
- Kazakov DV et al. Spiradenocarcinoma — review. Am J Surg Pathol; 2009.
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