Rare Cancers in Children

Desmoplastic Small Round Cell Tumor (DSRCT)

Desmoplastic Small Round Cell Tumor (DSRCT) is a rare, aggressive mesenchymal tumor.  (DSRCT) is seen predominantly in adolescents and young adults and rarely in children.  Desmoplastic Small Round Cell Tumor (DSRCT) is more common in young men and boys. Translocation -t (11; 22), (p13; q12). Produces a chimeric gene with an oncogenic potential called the EWS-WT1 gene (Ewing's sarcoma and Wilms tumor).

Clinical Features

A bulky abdominal mass , multiple peritoneal and omental implants. Symptoms of abdominal sarcomatosis: abdominal pain, features of intestinal obstruction, ascites, hydronephrosis, and progressive weight loss.

Sites of Metastasis

Lymph nodes > lungs > liver > bones.

Also read: Langerhans Cell Histiocytosis in Children

Diagnosis of Desmoplastic Small Round Cell Tumor (DSRCT)

Imaging: Ultrasound, MRI and pet scan 

Biopsy

Management of Desmoplastic Small Round Cell Tumor (DSRCT)

Multimodality therapy: Combination of chemotherapy, abdominopelvic radiation therapy, and debulking surgery. But this is not completely effective. Newer therapies include hyperthermic intraperitoneal chemotherapy and radiolabeled or specific targeted monoclonal antibodies.

Survival Rate 

5 year survival rate < 20% of the affected. The median survival rate is between 17 and 25 months.

Also read: Germ Cell Tumors In Children

Nasopharyngeal Carcinoma (NPC)

Rarely tumors in children but quite often in adolescents. Most commonly seen in south China is the adult population. Commonly reported in adolescent populations and adults from northeast India and North Africa. Certain studies have shown that the polyhydrocarbons released on excessive burning of incense sticks and bamboo wood have a significant role in the causation of the disease.

Influence of HLA predisposition, genetic predisposition, and Epstein-Barr virus infection in the causation of this disease. Males > females, Africans, and Asians > Caucasians. The common site of origin is the fossa of Rosenmuller. The two characteristic features of pediatric NPC are:

• Undifferentiated and aggressive types of tumors.
• Strongly associated with Epstein-Barr virus infections.

Clinical Features

Most pediatric patients present with cervical lymphadenopathy due to the relatively early spread to the local limb. Unilateral or bilateral.

Common features are nasal obstruction, nasal discharge, epistaxis, trismus, and conductive hearing loss due to eustachian tube block. Cranial nerve palsies can occur due to both CNS and peripheral nerve involvement. Horner's syndrome is seen in sympathetic ganglion involvement cases.

Also read: Leukemias In Children

Investigations and Management in NPC

X-ray neck and nasopharynx. CT or MRI of the head and neck region are done, particularly in the nasopharyngeal region. Findings of mass, then a CT-guided biopsy should be done. Biopsy samples can be obtained from enlarged lymph nodes as well. For metastasis, chest X-ray, CT chest, and PET scan. EBV-DNA estimation:

• Stage of the disease.
• Diagnostic clue.
• Recurrence prediction.

Management

Surgery management is not useful. In the early stages, radiotherapy alone is beneficial. In the late stage of pediatric NPC, radiotherapy and chemotherapy are done.

• Cisplatin is the drug of choice in chemotherapy.
• Nowadays, radiotherapy is often replaced with IMRT (intensity-modulated radiation therapy).

Colorectal Cancers in Children 

Occur very rarely in children. They occur mostly as a part of syndrome. The common syndromes associated are FAP syndrome, attenuated FAP syndrome, or hereditary nonpolyposis colorectal cancer. Rarely can it occur in association with Peutz-Jeghers syndrome or juvenile polyposis. Most pediatric colorectal cancer is of the mucinous adenocarcinoma or signet ring cell carcinoma variety. Clinical features include bleeding per rectum, bloody stool, constipation, tenesmus, features of metastasis, etc. Diagnosis is often delayed, as it is a rare disease and less suspected. 

Management: Combination of surgeries with or without chemotherapy.

Also read: High-Yield NEET SS Pediatric Oncology Questions

Points to Remember

• Trotter's triad is a set of 3 features, especially seen in nasopharyngeal carcinoma. The features of the triad are:
  • Conductive deafness due to Eustachian tube blockage.
  • Ipsilateral temporoparietal neuralgia due to trigeminal nerve involvement.
  • Palatal palsy due to vagal nerve involvement.
• Multimodality therapy: Combination of chemotherapy, abdominopelvic radiation therapy, and debulking surgery

Hope you found this blog helpful for your NEET SS Pediatrics Oncology preparation. For more informative and interesting posts like these, keep reading PrepLadder’s blogs.