Testis Cancer, Anatomy, Embryology Flashcards
Gene that determines gonadal transition to a male
SRY
Under the influence of the SRY gene (sex-determining region of the Y chromosome), in the 7th to 8th week, cells in the genital ridge differentiate into seminiferous tubules containing spermatogonia and Sertoli cells. Without the SRY protein, ovarian follicles form.
The Sertoli cells begin to secrete Müllerian-inhibiting substance (MIS), acting locally and causing the Müllerian ducts to regress between 8-10 weeks, thus contributing to normal male phenotypic development.
Which cells produce testosterone?
Leydig cells
In the 9th-10th weeks, Leydig cells differentiate from genital ridge cells in response to SRY protein and are located between the seminiferous tubules. These cells begin to produce testosterone. There is a rise in both serum and testicular testosterone that peaks at 13 weeks before beginning to decline.
Between the 8th and 12th week, testosterone secretion stimulates the virilization of the wolffian ducts into the vas deferens, seminal vesicles, and ejaculatory ducts.
Table of timing of male gonadal development
Normal adult testis size and volume
On average, the normal adult testis measures 4-5cm long, 3cm wide, and 2.5cm deep with volume ranging 12-30ml.
Three types of histologic cells in testis
Seminiferous tubules, Sertoli cells, Leydig cells
Arterial blood supply to testis
Three:
1. Gonadal/Testicular
- Arises inferior to SMA, directly off of aorta
2. Cremasteric
- Arises from inferior epigastric artery
- Anastomoses with testicular artery within testis
3. Vasal
Left Testicle Lymphatic Drainage
The primary drainage pattern on the left is to the para-aortic and preaortic lymph nodes, followed by the interaortocaval nodes.
Right Testicle Lymphatic Drainage
On the right side, primary drainage is to the interaortocaval nodes, followed by the precaval and preaortic nodes.
It is more common for the lymphatic drainage of the right testis, and rare with left-sided tumors, to cross the midline and exhibit bilateral lymph node metastases
Drainage is right to left!
Layers of the scrotum and spermatic cord encountered during surgical exploration, progressing from superficial to deep
Skin, dartos, external spermatic fascia, cremasteric fascia, cremasteric muscle, internal spermatic fascia, tunica vaginalis (parietal then visceral), tunica albuginea
T staging of testicular tumors
N staging of testicular cancer
M staging of testicular cancer
Serum Tumor Marker Staging
Stage Grouping
Risk Classification for Sem and Non-Sem
Treatment options for stage IA and IB pure seminoma
(i) Surveillance (preferred)
(ii) Retroperitoneal Radiotherapy
(iii) Chemotherapy with carboplatin (1 or 2 cycles)
More than 80% of patients with stage I seminoma are cured with orchiectomy alone, therefore surveillance is the preferred approach, and the disease specific survival for stage I disease is 99% irrespective of the management strategy used.
AUA Guideline Algorithm for treatment of early testicular cancer
Surveillance for Stage IA and IB Seminoma
Risk factors for predicting relapse
In an analysis of over 600 patients, rete testis invasion and tumors ≥ 4 cm were identified as risk factors for predicting relapse.
For patients with 0, 1, or 2 of these risk factors the recurrence rates were 12%, 16%, and 32%, respectively.
NCCN recommends against a risk-adapted approach and supporting surveillance as the preferred strategy for all stage I patients.
Stage I Seminoma Surveillance NCCN and AUA
Types of testicular cancer
The vast majority are classified as germ cell tumors (95%), while the remaining are predominately sex cord/stromal tumors (mainly Leydig cell and Sertoli cell tumors). Germ cell tumors (GCT) are further designated as seminoma or non-seminoma germ cell tumors (NSGCT).
Risk factors for developing testicular cancer
Cryptorchidism, personal or family history, intra-tubular germ cell neoplasia (ITGCN).
It is felt that most GCTs arise from ITGCN and its presence is a major risk factor as 50% of men with ITGCN will develop a GCT within 5 years.
Histologic Subtypes of Testicular Cancer
Germ Cell Tumors:
- Seminoma
- Nonseminomatous Germ Cell Tumors: Embryonal, Choriocarcinoma, Teratoma, Yolk Sac (Endodermal Sinus Tumor)
Does Seminoma produce AFP? bHCG?
NO AFP
5% produce bHCG (because 5% contain syncytiotrophoblasts, which secrete bHCG)
