Germ cell tumors

Primordial germ cells undergo genomic imprinting during normal development involving erasure of the biparental modifications and establishment of a uniparental pattern.

Account for the vast majority, 95%, of testicular cancers.

In 2017 they were an estimated 8850 new cases in 400 deaths in the US.

Classified as seminomatous or nonseminomatous..

Seminomas, account for 50% of all germ cell tumors, tend to be less aggressive than non-seminomatous tumors and follow a relatively predictable course.

While approximately 80% of patients with seminomatous germ cell tumors present with stage I disease, 66% of patients with nonseminomatous GCT’s present with stage II or III disease.

Seminoma is a very sensitive to radiation and chemo therapy and visceral metastases are uncommon.

When seminomas spread, they usually spread to the retroperitoneal lymph nodes.

Hypomethylation seen in testicular germ cell tumors consistent with primordial germ cell/gonocyte origin of seminomas and non-seminomas in which genomic imprinting has been erased.

Higher risk with Cryptorchidism, Klinefelter’s syndrome, Down’s syndrome, testicular feminization and true hermaphrodites.

Up to six fold increases in family members.

Increased incidence of 2242 disease.

Only 3-5% of patients with metastatic disease and complete remission will develop recurrent disease, such patients are observed.

Of the patients with metastatic disease treated with chemotherapy and with residual radiographic tumor or abnormal serum tumor markers patients undergo post chemotherapy retroperitoneal lymph node dissection.

Pathology findings in patients undergoing post chemotherapy surgery for residual disease are found to have necrosis in 45% of cases, teratoma in 45% of cases and cancer in 10% of cases.

Surgical resection of necrotic tissue after chemotherapy offers no benefit to patients, and the finding of necrosis is a staging procedure only.

The rate of disease recurrence in the population of patients with surgical findings of necrosis is less than 5%.

Patients with fibrosis alone found after chemotherapy and retroperitoneal lymph node dissection have a 93% progression free survival (Donohue).

Postchemotherapy resection of residual tumor or teratoma is accepted management as both entities may increase in size and metastasize.

For patients with refractory disease standard does chemotherapy is rarely curative.
For residual teratoma surgery is the only option since it is not sensitive to chemotherapy.

Rate of recurrence of disease after resection of a teratoma residual is equal or less than 10%, with increased possibility of recurrence with larger volume of disease (Loeher).

About 7000 cases of extragonadal germ cell tumors annually in the U.S.

Extragonadal are characterized by midline locations including the mediastinum (50-70%), retroperitoneum (30-40%) and other areas such as the pelvis and pineal gland.

Classified as benign teratomas or malignant.

Malignant lesions divided into seminomas (30-40%) and nonseminomas (60-70%) with the latter subtypes of embryonal, yolk-sac, endodermal sinus, choriocarcinoma, malignant teratoma or a combination.

5-year survival for patients with primary mediastinal GCT is 40%.

Patients with GCT of the mediastinum and fail first-line chemotherapy have a poor salvage chemotherapy response with less than 10% long-term survivors.

Surgical resection of residual mediastinal mass after chemotherapy is and integral part of management of patients with primary mediastinal GCT.

Of the ovary are almost exclusively diagnosed in young females.

Of the ovary are only rarely bilateral.

Of the ovary should be treated with conservative surgical approach.

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