Introduction
A renal pelvic carcinoma is a rare type of kidney cancer. Urinary tract clear cell adenocarcinoma is uncommon and resembles the female genital tract histomorphology. The diagnosis may be supported by the immunohistochemistry staining. Owing to its rarity, a successful treatment plan has not yet been established. This article reviews in detail about clear cell adenocarcinoma of the pelvis.
What Is the Renal Pelvis?
The renal pelvis is an enlarged funnel-shaped region through which urine passes. It fills the renal sinus and is situated within the kidney's medial, concave surface. The renal pelvis apex grows outward from the kidney and joins the upper end of the ureter at its peak. Nephrons in the kidney produce urine. After that, the liquid passes via several tubes and funnel-shaped structures to reach the urine bladder.
What Is Clear Cell Adenocarcinoma?
Clear-cell adenocarcinoma is an adenocarcinoma (cancer that develops in glands) with clear cells. Clear cell tumors are a type of adenocarcinoma in which the majority or all of the epithelial cells are non pseudostratified, columnar to cuboidal, and have clear cytoplasm. The female genital tract, which includes the vagina, uterine cervix, endometrium, and ovary, is where clear cell adenocarcinoma (CCA) typically develops as a separate entity.
Clear cell adenocarcinoma is an uncommon tumor of the urinary system. It typically affects women's lower urinary tracts, primarily the urethra. While clear-cell adenocarcinoma of the female genital tract has a bad prognosis, clear-cell adenocarcinoma of the lower urinary system is not as aggressive as previously thought. Since many of these tumors exhibit an exophytic development pattern, they may be identified early and have a favorable prognosis. Clear cell adenocarcinoma of the upper urinary tract is extremely rare.
What Is Clear Cell Adenocarcinoma of the Renal Pelvis?
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Clear cell adenocarcinoma of the urinary system is an uncommon tumor that primarily affects the lower urinary tract, particularly the urethra. This unique neoplasm shares the same morphology as the corresponding neoplasm that develops in the female vaginal organs.
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The urinary tract's clear cell adenocarcinoma was first identified as mesonephric carcinoma since it was thought to have a mesonephric origin. Clear cell adenocarcinoma was also thought to be of urothelial origin.
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According to fluorescence in situ hybridization assays, clear cell adenocarcinomas showed genetic abnormalities in a recent study that were exactly the same as those frequently seen in urothelial cancer. X-chromosome inactivation study also demonstrated a shared clonal origin in two cases of clear cell adenocarcinoma and urothelial cancer.
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A nephrogenic adenoma is a crucial differential diagnosis for clear cell adenocarcinoma. There have been a few documented instances where morphological or molecular evidence indicates that nephrogenic adenoma of the bladder progresses to clear cell adenocarcinoma.
How Common Is Clear Cell Adenocarcinoma of the Renal Pelvis?
Renal pelvic carcinoma accounts for about seven percent of all renal neoplasms. Most renal pelvis cancer cases had a histology of conventional urothelial (transitional cell) tissue. Just one percent of instances of carcinoma in the renal pelvis are adenocarcinoma, making it an uncommon kind of cancer.
Urinary tract clear cell adenocarcinoma (CCA) is an uncommon histologic subtype of adenocarcinoma. The tumor's histomorphological characteristics are similar to those of Mullerian origin or clear cell adenocarcinoma of the female vaginal tract. Reports of clear cell adenocarcinoma in the urethra and bladder have totaled about 70 and 90 cases, respectively. On the other hand, upper urinary tract clear cell adenocarcinoma is extremely uncommon.
What Are the Clinical Features of Clear Cell Adenocarcinoma of the Renal Pelvis?
Clear cell adenocarcinoma in the female genital tract is well-known as a high-grade, aggressive malignancy with a tendency for treatment resistance. Recent research on lower urinary tract CCA has revealed that the tumor exhibits fairly aggressive behavior. Only 24 percent of patients remained alive with no indication of cancer after treatment, while the majority (76 percent) either died of disease or had recurrence or advanced cancer (40 percent) or both. Given that the tumor cells exhibited CA-125 immunoexpression and that there has previously been documentation of raised serum CA-125 levels, CA-125 may be employed as a serologic tumor marker in the clinical follow-up. Since clear cell adenocarcinoma in the urinary system is uncommon, a successful treatment plan has not yet been established.
What Are the Histologic Features of Clear Cell Adenocarcinoma of the Renal Pelvis?
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The histogenetic origin of clear cell adenocarcinoma in the urinary system is uncertain. Nephrogenic adenoma, urothelium, mesonephric duct remnants, or Mullerian duct derivatives have all been suggested as potential sources of the tumor.
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The urothelial origin of this tumor was substantiated by recent investigations utilizing immunohistochemical stains and molecular genetic studies, despite the tumor's peculiar form that is comparable to or indistinguishable from clear cell adenocarcinoma of Mullerian origin and the substantial prevalence of female patients.
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These results are consistent with the fact that half of the cases of clear cell adenocarcinoma in the lower urinary tract also have concurrent urothelial carcinoma (invasive or in situ), and one-third have cystitis glandularis.
How Is Clear Cell Adenocarcinoma Diagnosed?
The clinical difference between clear-cell adenocarcinoma and other kinds of urothelial carcinoma with clear cell characteristics is still unclear due to the rarity of clear-cell adenocarcinoma in the renal pelvis. Positive HNF and PAX8 (or PAX2) immunoreactivity aids in the exclusion of non-clear cell adenocarcinoma forms of urothelial carcinoma. A differential diagnosis of clear cell adenocarcinoma could include nephrogenic adenoma, a benign lesion in the urinary system with a tubulopapillary architecture and localized clear or hobnail cells. The primary indicators for the diagnosis of clear cell adenocarcinoma are the existence of obvious nuclear pleomorphism, diffuse nuclear hyperchromasia, and a high mitotic rate.
Conclusion
Clear cell adenocarcinoma of the renal pelvis is a very rare tumor. Urinary tract clear cell adenocarcinoma is uncommon and resembles the female genital tract histomorphology. Histologically, clear cell adenocarcinoma of the renal pelvis can be difficult to diagnose, especially when trying to differentiate it from renal cell carcinoma. The diagnosis may be supported by the immunohistochemistry staining. Because of its rarity, an effective treatment regimen is still undetermined.
