Seminal vesicle amyloidosis
Amyloid deposition in the seminal vesicles is apparently commonly seen in elderly men with a prevalence ranging from 16%-21% is more commonly seen in the localized form 1-3. It has been also reported in up to 10% of radical prostatectomy specimens.
Clinically seminal vesicle amyloidosis can present with hematospermia.
Amyloid deposits of the seminal vesicles occur characteristically in the subepithelium or the lamina propria with the involvement of both seminal vesicles in the localized form. On the other side amyloid deposits in vessel walls or within the muscular tissue indicates systemic amyloidosis 1,3.
In the seminal vesicles, amyloid is apparently derived from semenogelin 1, which is a secretory product of the seminal vesicles and is thought to have a role in the localized form 4.
Amyloidosis is characterized by the deposition of amyloid fibrils in the extracellular space which appears as an apple-green birefringence under polarized light and can be positively stained with Congo red 1. Beyond that amyloid looks like an amorphous pale eosinophilic substance that often features cracks.
Immunohistochemistry stains are usually positive for AP protein in localized amyloidosis. Tryptophan was
Imaging features of seminal vesicle amyloidosis on magnetic resonance imaging show some similarities with seminal vesicle invasion and include:
- wall thickening
- luminal narrowing
Other than seminal vesicle invasion seminal vesicle amyloidosis does not tend to show any diffusion restriction or early contrast enhancement 5.
- T1: hyperintense
- T2: hypointense walls
- DWI: lack of diffusion restriction
- DCE (Gd): lack of normal enhancement
The radiological report should include a description of the following:
- luminal narrowing
- associated findings of the prostate
History and etymology
There are diverse descriptions of amyloid in the seminal vesicles in the 1920s e.g. by M Winkelmann in 1927 6.
Conditions that may mimic the clinical presentation or imaging appearance of 2-4:
- 1. Pitkänen P, Westermark P, Cornwell GG, Murdoch W. Amyloid of the seminal vesicles. A distinctive and common localized form of senile amyloidosis. (1983) The American journal of pathology. 110 (1): 64-9. Pubmed
- 2. Kim B, Kawashima A, Ryu JA, Takahashi N, Hartman RP, King BF. Imaging of the seminal vesicle and vas deferens. (2009) Radiographics : a review publication of the Radiological Society of North America, Inc. 29 (4): 1105-21. doi:10.1148/rg.294085235 - Pubmed
- 3. Ramchandani P, Schnall MD, LiVolsi VA, Tomaszewski JE, Pollack HM. Senile amyloidosis of the seminal vesicles mimicking metastatic spread of prostatic carcinoma on MR images. (1993) AJR. American journal of roentgenology. 161 (1): 99-100. doi:10.2214/ajr.161.1.8517333 - Pubmed
- 4. Rath-Wolfson L, Bubis G, Shtrasburg S, Shvero A, Koren R. Seminal Tract Amyloidosis: Synchronous Amyloidosis of the Seminal Vesicles, Deferent Ducts and Ejaculatory Ducts. (2017) Pathology oncology research : POR. 23 (4): 811-814. doi:10.1007/s12253-017-0193-7 - Pubmed
- 5. Reddy MN, Verma S. Lesions of the Seminal Vesicles and their MRI Characteristics. (2014) Journal of clinical imaging science. 4: 61. doi:10.4103/2156-7514.143734 - Pubmed
- 6. Über lokales Amyloid der Samenblasen. (1927) Virchows Archiv für pathologische Anatomie und Physiologie und für klinische Medizin. 265 (2): 524. doi:10.1007/BF01894182