General Surgery – Renal & Ureteric Calculi MCQs (Part 2)

• Rim and ball nephrogram on IVP is seen in chronic obstructive nephropathy.
• Rim sign is seen in chronic hydronephrosis.

Classification of RCC:

• Clear cell carcinoma:
− MC type of RCC, mainly sporadic.

• Both sporadic and familial cases are associated with loss of sequence on                             chromosome 3 either by translocation (3:6, 3:8, 3:11) or deletion.
• This region harbors the VHL gene.

− Arise from proximal tubular epithelial cells particularly of cortex.
− Occurs as solitary unilateral lesion, often a pseudocapsule is formed around tumor           by compression of surrounding tissue.
− Tumor cells are clear and contain glycogen & lipids.
− Most are well differentiated.

• Papillary carcinoma:
− Characterized by papillary growth pattern.                                                                                      • MC cytogenetic abnormalities are trisomies 7, 16, and 17.
• Loss of 18 in sporadic form, trisomy 7 in familial form.
• This is due to mutated MET gene on chromosome 7.                                                    − Arise from DCT, can be multifocal and bilateral.
− Typically hemorrhagic and cystic.
− Papillary carcinoma is the MC type of RCC in patients with dialysis associated cystic      disease.
− Composed of cuboidal and low columnar cells.
− Psammoma bodies may be present.
• Chromophobe renal carcinoma:
− Represent 5% of RCC, composed of cells with prominent cell membrane and                    eosinophilic cytoplasm with a halo around nucleus.
− Relative transparent cytoplasm with a fine reticular pattern described as ‘Plant cell’        appearance.
− Associated with best prognosis
• These tumors exhibit multiple chromosome loss and extreme hypodiploidy.
• Loss of multiple chromosomes 1, 2, 6, 10, 13, 17, 21 and Y.
− Arises from intercalated cells of collecting duct.
− Composed of pale eosinophilic cells often with a perinuclear halo.                                   • Collecting duct (bellini duct) carcinoma:
− Rarest type of RCC, composed of malignant cells enmeshed within a prominent                fibrotic stroma typically in medullary location.
− Arise from collecting duct cells in the medulla.
− Has got very aggressive course.                                                                                                  • Remember: Medullary cell carcinoma is seen almost exclusively in association                 with sickle cell trait.                                                                                                               Renal Cell Carcinoma:                                                                                                              • MC type of RCC: Clear cell carcinoma.
• MC type seen with dialysis associated cystic disease: Papillary carcinoma.
• Exclusively associated with sickle cell trait: Medullary cell carcinoma.
• Best prognosis: Chromophobe carcinoma.

Oncocytoma:

• Represents 3–7% of all solid renal masses.
• Most renal oncocytomas cannot be differentiated from eosinophilic malignant                  RCC by clinical or radiographic means.

Pathology:
• In grossly, tumors are light brown or tan, homogeneous, and well circumscribed,            not truly encapsulated.
• A central scar without prominent necrosis or hypervascularity.
• Ultrastructurally, packed with numerous large mitochondria, which contributes to          their distinctive staining characteristics.
Diagnosis:
• CT scan: Central stellate scar.
• Angiography: Spoke-wheel pattern of feeding arteries
• MRI: well-defined capsule, central stellate scar, and distinctive intensities on T1                and T2 images.                                                                                                        Treatment:
• A nephron-sparing approach is preferred.

• These tumors exhibit multiple chromosome loss and extreme hypodiploidy.
• Loss of multiple chromosomes 1, 2, 6, 10, 13, 17, 21 and Y.