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Table 1 Reported cases of SOM in papillary urothelial carcinoma of the bladder

From: Stromal osseous metaplasia in urothelial carcinoma of the bladder: a rare case report and literature review

Case Age-Sex Tumor site, description ± related circumstances Histological findings IHC profile within the metaplastic component Treatment Pathologic stage and grade at the diagnosis Outcome Reference
1 60y-F Almost entire bladder: firm and irregular ulcerated mass, extremely fixated to the bladder wall with areas of calcification, 6y. after BTR and repeated cystodiathermy cauterization for bladder tumor. -WD PUC
-SOM characterized by thick lamellated mature bone trabeculae, outlined by osteocytes and surrounded by osteoid material.
-Other findings: squamous metaplastic changes, calcified material, no cartilage formation.
WNP Partial cystectomy. pT2G3 NA [1]
2 50y-M Anterior, posterior and lateral bladder wall: multiple, nodular and partially pedunculated growths, 4y. after BTR and various occasions of cystodiathermy cauterization. -Papillary urothelial tumor with doubtful stromal invasion.
-SOM characterized by osteoid and multiple slender bone trabeculae, lamellated or coarse – fibred, outlined by active osteoblasts and small osteoclasts.
- Other finding: no cartilage formation.
WNP Cystodiathermy cauterization after biopsy. p TxG1 Free from lesions and symptoms 5y after biopsy. [1]
3 68y-M Bladder, NOS. -WD PUC
-SOM: osteoid material and bone trabeculae, NOS
-Other finding: no cartilage formation.
NA NA p TxG2 NA [2]; [4]
4 65y-M Right and left sides of the bladder wall: respectively
large infiltrating solid tumor and papillary growth pattern.
Right side solid tumor:
-PD urothelial carcinoma.
-SOM: osteoid formation without mineralization.
-Other findings: squamous metaplastic changes; focal calcification; no cartilage formation.
Left side papillary tumor:
WNP Radiotherapy after biopsies. p T1G2 Died of pyelonephritis. [4]
5 56y-M Hard solid bladder tumor, NOS. -WD PUC
-SOM: several bone trabeculae mostly calcified without visible osteoblasts.
-Other findings: bone marrow- like spaces containing fat, reticulum and capillaries, without hematopoietic elements; squamous metaplastic changes, no cartilage formation
WNP Left the hospital without further treatment after biopsy. p TxG2 NA [4]
6 66y-M Superior to the left ureteral orifice and posterior bladder wall: papillary stalked tumors, 18 m. after partial cystectomy and right ureteroneocystostomy for papillary urothelial carcinoma. -MD PUC
-SOM: osteoid formation with fibroblasts and osteoblasts in surrounding stroma.
-Other finding: no cartilage formation.
WNP Total cystectomy with pelvic lymphadenectomy and ureterosigmoidostomy. p TxG2 Alive and well after surgery. [6]
7 85y-F Retrotrigonal region: solitary and pedunculated bladder tumor. -PD PUC
-SOM: osteoid material and bone trabeculae, NOS.
-Other finding: cartilage formation.
WNP -Repeated transurethral BTR.
-Total cystectomy and ileal conduit diversion.
p T2b G3 NA [7]
8 84y-M Bladder neck: large exophytic tumor; 4y. after retropubic prostatectomy for prostatic hyperplasia, 5y. history of bladder urothelial carcinomas with TUBR and a 6-week course of intravesical thio-tepa. -PUC with extensive glandular differentiation.
-SOM: scattered foci of osteoid, often surrounded by flattened cells resembling osteoblasts.
-Other findings: focal calcification, no cartilage formation.
WNP TUR. p T2 G3 Alive with disease 7 m. after last tumor resection. [2]
9 60y-M Posterior bladder wall: ill-defined sessile mass with hemorrhagic ulceration; 5 m. after TUR-prostate for benign prostate hyperplasia on which a tumor was seen and interpreted as NV-UC. -NV- UC: small nests and cords of uniform cells with occasional tubular structures.
-SOM: mature and laminated bone trabeculae with benign osteocytes.
WNP on metaplastic components. Radical cystoprostatectomy with adjuvant chemotherapy. p T4a Nx Mx Died of metastatic disease 11 m. after the first diagnosis. [8]
10 64y-M Lateral and posterior bladder wall: multiple nodular lesions; 26y. history of bladder amyloidosis treated by repeated TUR (6 times, last 7y. ago). -SUC with sarcomatoid differentiation and amyloidosis
WNP Radical cystectomy with ileal conduit and adjuvant chemotherapy. p T3b G3 N1 M0 Alive and well. [9]
11 66y-M Posterior bladder wall: firm white – tan mass with an extensive area of ossification near the right seminal vesicle. -PUC, NOS
-SOM: mature lamellated bone trabeculae outlined by osteoblasts.
WNP -Radical cystoprostatectomy.
-Chemotherapy (weekly taxane injection).
-External beam radiotherapy.
p T4b G3 NA [10]
12 3y-M Posterior bladder wall: exophytic papillomatous tumor with a thin stalk. -PUC
-Other findings: glandular and squamous metaplasia.
WNP on metaplastic bone. -TUR. p T1 G3 Free from lesions at 2y. follow-up. [5]
13 83y-M Right side of the bladder wall: whitish and firmer nodular growth, 13y. after RP, adjuvant radiotherapy and annual injection of leuprorelin (enantoneR) for prostatic adenocarcinoma. -WD PUC with focal component of urothelial carcinoma in situ.
-SOM: multiple bone trabeculae, lamellated or coarsed-fibred with osteoid seams outlined by osteoblasts and osteoclasts.
-Other finding: no cartilage formation.
-CD56+ on osteoblasts.
-CD68+ on osteoclasts.
-Mild positivity of PS100 and P53 in osteoid areas and bone trabeculae.
-MDM2-, CDK4-.
-Ki 67 + 20%.
TUBR with adjuvant BCG therapy. p T1 G3 -Two local recurrences over an 8-month follow-up period.
-Alive and well at the time of the report.
Present case
  1. IHC Immunohistochemical, NA not available, NOS not otherwise specified, WNP was not performed, SOM stromal osseous metaplasia, y years, m month, PUC papillary urothelial carcinoma, SUC solid urothelial carcinoma, NV-UC nested variant urothelial carcinoma, PD poorly differentiated, MD moderately differentiated, WD well differentiated, BTR bladder tumor resection, TUR transurethral resection, TUBR transurethral bladder resections, RP radical prostatectomy