TY - JOUR
T1 - Microsecretory adenocarcinoma of the skin harboring recurrent SS18 fusions
T2 - A cutaneous analog to a newly described salivary gland tumor
AU - Bishop, Justin Avery
AU - Williams, Erik A.
AU - McLean, Anne C.
AU - Gagan, Jeffrey
AU - Rooper, Lisa M.
AU - Jordan, Richard C.K.
AU - LeBoit, Philip E.
N1 - Funding Information:
This study was funded by the Jane B. and Edwin P. Jenevein M.D Endowment for Pathology at UT Southwestern Medical Center.
Publisher Copyright:
© 2022 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.
PY - 2022
Y1 - 2022
N2 - Background: Microsecretory adenocarcinoma (MSA) is a newly described salivary gland neoplasm characterized by MEF2C::SS18 fusions. MSA was previously thought to occur exclusively in salivary glands. Here, we expand the spectrum of known primary sites of this tumor by describing a series of cutaneous tumors with analogous findings. Methods: We identified four cutaneous primary tumors with histopathologic features identical to MSA of the salivary glands. These cases were evaluated by immunohistochemistry, fluorescence in situ hybridization (FISH) for SS18 rearrangement and targeted RNA-sequencing. We also queried a pan-tumor database of advanced carcinomas for MEF2C::SS18. Results: The cases occurred in men ranging from 61 to 74 years (mean, 68). They arose from the skin of the nose, chin, scalp, and external auditory canal. All included cords/microcysts of eosinophilic cells with bland oval nuclei and bluish mucin within fibromyxoid stroma. The scalp tumor also exhibited high-grade transformation (marked atypia, elevated mitotic rate, and necrosis), a feature unreported in salivary MSA. By immunohistochemistry, all cases were positive for S100. Two showed a myoepithelial component positive for p40 and smooth muscle actin or calponin. Three cases harbored MEF2C::SS18 by RNA sequencing, while one with limited tissue had SS18 rearrangement via FISH. Two patients had no evidence of recurrence or metastasis in limited follow-up (3 and 6 months). The pan-tumor database query also did not identify MEF2C::SS18 in any advanced cutaneous carcinomas. Conclusion: This report expands the sites that can be involved by MSA. Similar to salivary cases, MEF2C::SS18 represents a recurrent fusion in MSA of the skin. Unusual features in cutaneous cases not seen in salivary MSA include one case with high-grade transformation and two cases with a myoepithelial cell component. Identification of this fusion expands the spectrum of salivary-analog cutaneous tumors and aids in precise tumor classification.
AB - Background: Microsecretory adenocarcinoma (MSA) is a newly described salivary gland neoplasm characterized by MEF2C::SS18 fusions. MSA was previously thought to occur exclusively in salivary glands. Here, we expand the spectrum of known primary sites of this tumor by describing a series of cutaneous tumors with analogous findings. Methods: We identified four cutaneous primary tumors with histopathologic features identical to MSA of the salivary glands. These cases were evaluated by immunohistochemistry, fluorescence in situ hybridization (FISH) for SS18 rearrangement and targeted RNA-sequencing. We also queried a pan-tumor database of advanced carcinomas for MEF2C::SS18. Results: The cases occurred in men ranging from 61 to 74 years (mean, 68). They arose from the skin of the nose, chin, scalp, and external auditory canal. All included cords/microcysts of eosinophilic cells with bland oval nuclei and bluish mucin within fibromyxoid stroma. The scalp tumor also exhibited high-grade transformation (marked atypia, elevated mitotic rate, and necrosis), a feature unreported in salivary MSA. By immunohistochemistry, all cases were positive for S100. Two showed a myoepithelial component positive for p40 and smooth muscle actin or calponin. Three cases harbored MEF2C::SS18 by RNA sequencing, while one with limited tissue had SS18 rearrangement via FISH. Two patients had no evidence of recurrence or metastasis in limited follow-up (3 and 6 months). The pan-tumor database query also did not identify MEF2C::SS18 in any advanced cutaneous carcinomas. Conclusion: This report expands the sites that can be involved by MSA. Similar to salivary cases, MEF2C::SS18 represents a recurrent fusion in MSA of the skin. Unusual features in cutaneous cases not seen in salivary MSA include one case with high-grade transformation and two cases with a myoepithelial cell component. Identification of this fusion expands the spectrum of salivary-analog cutaneous tumors and aids in precise tumor classification.
KW - cutaneous adenocarcinoma
KW - MEF2C::SS18
KW - microsecretory adenocarcinoma
KW - SS18 fusion
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U2 - 10.1111/cup.14271
DO - 10.1111/cup.14271
M3 - Article
C2 - 35690998
AN - SCOPUS:85133657382
SN - 0303-6987
JO - Journal of Cutaneous Pathology
JF - Journal of Cutaneous Pathology
ER -