The SAC component of these lesions consists of cells that, along with their nuclei and cytoplasm, vary greatly in size and shape. The cells may be rapidly proliferating, have atypical mitosis figures, and may be invading nearby neural or lymphovascular structures; they do not arrange into intertwining strips of small and large cells. High-grade SAC tissues show a more severely disturbed architecture, more marked variation in cell, nuclei, and cytoplasm sizes and shapes, and more rapidly proliferating cells than low-grade SAC tissues. SAC tumor tissues may show various other features, e.g. they may closely resemble sarcomas. In rare cases, SAC has been reported to apparently arise de novo, i.e. begin as malignant lesions. Gene abnormalities
Studies indicate that a minority of SA and SAC cases have one of two potentially disease-causing mutations in their tumor cells: loss-of-function (i.e. gene-inactivating) mutations in the CYLD gene in 5 of 17 SA and 2 of 24 SAC cases or gain-of-function (i.e. gene-activating) mutations in the ALPK1 gene in 7 of 16 SA and 4 of 14 SAC cases. The two mutations are mutually exclusive, i.e. do not occur together in any individuals tumor(s). Both mutations result in blocking the actions pf NF-κB. NF-κB is a transcription factor which acts indirectly to stimulate the expression of various genes that trigger cell death by apoptosis and necroptosis and also inhibit cell proliferation (see CYLD genes mechanism of action).
Each check-up should incorporate the examination of the patients regional lymph nodes and on a case-by-case basis annual chest X-rays and liver function tests. Spiradenomas
The currently preferred treatment for sporadic SA tumors (including giant vascular eccrine SA) in almost all cases is surgical excision. Many studies recommend wide local surgical excision of these tumors with surgical margins of ≥1 cm in order to ensure that all tumor cells are removed: local lymph node resections are usually reserved for those cases suspected of having lymph node metastases. Mohs micrographic surgery has been used as an alternative to surgical excision for the complete removal of these tumors. Since SA tumors may contain unidentified areas of malignancy and therefore have high recurrence rates, may metastasize to local lymph nodes and/or distant tissues, and can result in overall poor survival times, adjuvant radiation therapy has been used to minimize these aggressive events in SA tumors with equivocal signs of malignancy. However, the effectiveness of these adjuvant therapies has not been established. Adjuvant CO2 laser treatments have been used on occasion to remove these tumors in cases with multiple tumors. Some trials have using botulinum toxin A and triamcinolone injections directly into SA tumors but these trials have had limited success. Spiradenocarcinomas
With only 117 malignant cases reported in the literature as of 2022, there are no standard guidelines for the treatment of SAC tumors. Localized (i.e.