Microscopic Description:

A typical urothelial carcinoma is usually present

Discohesive single cells with eccentrically placed nuclei and abundant eosinophilic cytoplasm some can also be basophilic. Infiltrative with minimal stromal reaction

Important feature: Oedema of mucosa, is an indicator to find rare tumor cells

Subtypes:

  • Classic: signet ring-like morphology, loose aggregates forming cords
  • Pleomorphic can be rhabdoid and bizarre appearing
  • Desmoplastic: Tumor cells with a surrounding desmoplastic stromal response

Resemble the signet ring cells but lack extracellular mucin

Positive Stains: Pancytokeratin, GATA3, CD138 (Plasmacytoid tumor cells are often CD138 positive and can be misdiagnosed as a plasma cell neoplasm). CK7, CK20, Uroplakin II, EMA

Negative Stains: E-cadherin (loss of membranous staining due to mutations in CDH1 in most cases, similar to lobular breast carcinoma), ER, PR, mammoglobin, Alcian blue / mucicarmine CDX2, S100, CD45, synaptophysin, chromogranin, MUM1

Discussion:

Plasmacytoid carcinoma of the urinary bladder is a rare histologic variant of transitional cell carcinoma (TCC) that often mimics hematologic malignancies and is characterized by a diffuse growth pattern and CDH1 mutation.

The age range is 45–78 years with male predominance with a history of smoking.

Sites- Bladder, Renal pelvis, Ureter (rare).

Clinical features: Gross or microscopic hematuria, dysuria, frequency, urgency, abdominal pain or hydronephrosis.

Elevated serum CA19-9 reported in a metastatic case.

Diagnosis: Cystoscopy may only show mucosal induration / thickening with no well-defined mass of focal mass

  • Sometimes linitus plastica-like
  • Followed by  transurethral biopsy and resection of tumor
References:

https://www.sciencedirect.com/science/article/pii/S0090429505000956. Iraklis C. Mitsogiannis, Maria G. Ioannou, Chrissanthi D. Sinani, Michael D. Melekos, Plasmacytoid transitional cell carcinoma of the urinary bladder, Urology, Volume 66, Issue 1,2005,Page 194,ISSN 0090-4295.

Teo, M.Y., Al-Ahmadie, H., Seier, K. et al. Natural history, response to systemic therapy, and genomic landscape of plasmacytoid urothelial carcinoma. Br J Cancer 124, 1214–1221 (2021). https://doi.org/10.1038/s41416-020-01244-2.

Benabdallah, Wajdi MDa; Ben Othmane, Mounaa; Ouahchi, Inesc; Mestiri, Sarrab; Belkacem, Oussamab; Bouassida, Khaireddinea; Hmida, Wissema; Jaidane, Mehdia. Plasmacytoid bladder cancer: a rare case report. Annals of Medicine & Surgery 85(5):p 1885-1887, May 2023. | DOI: 10.1097/MS9.0000000000000374

CASE IMAGES