CASE OF THE WEEK
2020-49 / December 7
Contributor: Connie Liao, Farshid Siadat
Penile lesion in a man in his 40s.
Quiz
1. What is the correct diagnosis?
a. Myointimoma
b. Leiomyoma
c. Neurothekeoma
d. Myofibroma
e. Neurofibroma
1. a
1. Myointimoma
Discussion: Myointimoma is a rare benign myointimal proliferation which occur exclusively in the corpus spongiosum of the glans penis. Architecturally, the lesion forms a plexiform pattern secondary to the extension of the pre-existing vascular network. The myointimoal proliferation is consist of predominantly bland spindle cells in an abundant fibromyxoid and fibrous stroma. The lesional cells are spindled and focally stellate with fine nuclear chromatin and variably eosinophilic cytoplasm. The lesional cells are positive for smooth muscle actin and desmin and negative for S-100. These lesions are thought to have a benign course and are cured by excisional biopsy (1, 2). Recognition of myointomoma is important to distinguish it from more aggressive histologic mimics.
1. Cito, G., Santi, R., Gemma, L. et al. Myointimoma of the penis. Int J Impot Res (2020). https://doi.org/10.1038/s41443-020-0316-7
2. McKenney JK, Collins MH, Carretero AP, Boyd TK, Redman JF, Parham DM. Penile myointimoma in children and adolescents: a clinicopathologic study of 5 cases supporting a distinct entity. Am J Surg Pathol. 2007;31:1622–6
Connie Liao (PGY5), chiuhsiang.liao@albertahealthservices.ca
Farshid Siadat, Farshid.siadat@albertaprecisionlabs.ca
University of Calgary
Calgary, Alberta
Penis
Penis, Soft Tissue, Mass