Posted in Histopathology, Nephropathology

5 Differences between perilobar and intralobar nephrogenic rests.

Nephrogenic rests are abnormally per­ sistent foci of embryonal cells (still pre­ sent after 36 weeks of gestation) that are potentially capable of developing into nephroblastoma (also called Wilms tumour). The presence of diffuse or multifocal nephrogenic rests is called nephroblastomatosis.

Nephrogenic rests are found in 25-40% of patients with nephroblastoma, and in approximately 1% of term infant autop­sies.

Nephrogenic rests can be found adjacent to nephroblastoma or in the surrounding renal parenchyma. They are classified into perilobar and intralobar types.

Here are 5 differences between perilobar and intralobar nephrogenic rests.

1. LOCATION

Perilobar nephrogenic rests are peripherally located, wheras intralobar nephrogenic rests are randomly intermingled between the renal parenchyma, typically located in the central areas of the lobe.

2. DEMARCATION FROM ADJACENT PARENCHYMA

Perilobar nephrogenic rests are sharply demarcated from the surrounding tissue, whereas intralobar nephrogenic rests are poorly de­marcated, usually infiltrate among native nephrons.

3. STROMA

Perilobar nephrogenic rests have scanty stroma, whereas intralobar nephrogenic rests are and are composed mainly of stromal and epithelial elements.

4. FOCALITY

Perilobar nephrogenic rests are usually multifocal whereas, intralobar nephrogenic rests are mostly unifocal (often single).

5. ASSOCIATED CONDITIONS

Perilobar nephrogenic rests are associated with hemihypertrophy and overgrowth syndromes such as Beckwith-Wiede­mann syndrome. lntralobar nephrogenic rests are associated with Denys-Drash syndrome (which is associated with nephroblastoma, pseudohermaphrodit­ ism, glomerulopathy, and renal failure) and WAGR syndrome (Wilms tumour / nephroblastoma, aniridia, genitourinary anomalies, and mental retardation syn­drome).

PERILOBAR AND INTRALOBAR NEPHROGENIC RESTS HISTOPATHOLOGIC PICTURES.

Difference between perilobar and intralobar nephrogenic rests.
Posted in Histopathology, Nephropathology, WEEKLY QUIZZES

Renal pathology quiz

Renal pathology quiz on 18/06/21

Useful for Pathology residents preparing for, NEET-SS/ DM- Oncopathology/ DM Histopathogy, Nephropathology Fellowships, FRCPath- Histopathology, American Board of anatomic and clinical pathology

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Posted in Histopathology, Nephropathology

Hereditary Renal Carcinoma syndromes

Hereditary Renal Carcinoma syndromes- Currently, there are 8 syndromes associated with an increased risk of all types of renal cancer.

1.Von Hippel Lindau (vHL) Disease

Salient features:  Patients with type 1 mutations (in general, truncating mutations) have a decreased incidence of pheochromocytoma as compared to those with type 2 mutations (in general, missense mutations). Families with type 2 mutations have either a high (type 2A) or low risk of ccRCC (type 2B); type 2C families only develop pheochromocytoma. 

2. Hereditary papillary renal cancer

Hereditary papillary renal cell carcinoma (HPRCC) is an autosomal dominant syndrome characterized by multifocal, bilateral type I papillary renal cell carcinomas.  Mutations of the MET gene on 7q31 have been causally associated with HPRCC, but MET is mutated in less than 10% of sporadic type papillary renal cancers. 

3. Hereditary leiomyomatosis and renal cell cancer (type 2 papillary)

Hereditary leiomyomatosis and renal cell cancer (HLRCC) is an autosomal cancer susceptibility syndrome characterized by the development of cutaneous and uterine leiomyomas and renal cancer. Papillary type 2 renal cancer is the pathological type most commonly associated with HLRCC, and tends to have an early age of onset, be high grade and have an aggressive course. The gene fumarate hydratase (FH), which encodes the enzyme which converts fumarate to malate in the Kreb’s cycle, is mutated in HLRCC.

4. BAP1 mutations and familial renal cancer

BAP1 mutations predispose to familial clear cell renal cancer, along with uveal and cutaneous melanoma and mesothelioma.

5. Chromosome 3 translocations

Increased loss of one allele leads to an increased risk of clear cell renal cancer.

6. PTEN hamartoma tumor syndrome (Cowden disease)

PTEN is associated with an increased risk of benign and malignant tumors of the thyroid, breast and endometrium caused by mutations in PTEN. Clear cell renal cancer has been reported as a observed in patients with Cowden syndrome.

7. SDH- associated paraganglioma/pheochromocytoma

Germline SDHB mutations are associated with increased risk of developing a variety of RCCs including clear cell, chromophobe, and oncocytomas.

8. Tuberous Sclerosis Complex

The 50 to 80% of patients with TSC who develop renal lesions can have angiomyolipomas (AMLs), cysts, oncocytomas, and renal cell carcinomas.

Reference: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3872053/

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Posted in Histopathology, Nephropathology

C3 Glomerulopathy- A new entity based on immunofluorescence

DEFINITION : C3 glomerulopathy is a recently defined entity that encompasses a group of kidney diseases caused by abnormal control of complement activation with deposition of complement component C3 in glomeruli leading to variable glomerular inflammation.

TYPES:  It is important to understand that,  C3 glomerulopathy involves a spectrum of disorders. 

1. DENSE DEPOSIT DISEASES

2. C3 GLOMERULONEPHRITIS

3. RARE CONDITIONS SUCH AS Complement factor H -R5 deficiency

4. OTHERS – Genetic variants in the C3CFBCFHCFI and CFHR1–CFHR5 genes are potentially causal; both rare and common variants can coexist and are associated with susceptibility to disease.

Complement Factor H is isajor negative regular of alternative complement pathway.

C3 Glomerulopathy- A new entity based on immunofluorescence
C3 glomerulopathy showing characteristic findings. Full article

DIFFERENTIAL DIAGNOSIS OF C3 GLOMERULOPATHY

1. Post- infectious glomerulonephritis- 30 % have C3 deposits alone. Hence clinical history can differentiate between the two.

2. Para-protein associated glomerulonephritis. Complement dysregulation may be caused due to paraproteins. Hence differentiation based on renal biopsy and Immunofluorescence alone is not possible.

3. Membranoproliferative glomerulonephritis

4. Cresentic glomerulonephritis.

C3 Glomerulopathy- A new entity based on immunofluorescence
Spectrum and differentials of C3 glomerulopathy. Full article.

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