Neoplasia III

• Important cancer types include:

  • Malignant melanoma
  • Sarcomas
  • Neuroendocrine neoplasms
  • Germ cell tumours
  • Other rare neoplasms including glial, embryonic, and borderline neoplasms
• Malignant melanoma:

  • Common sites: skin, anal margin, eye
  • Aetiology: ultraviolet radiation
  • Tumour of melanocytes
• In malignant melanoma, the 'ABCDE' stands for:

  • Asymmetry
  • Border irregularity
  • Color variation
  • Diameter greater than 6mm
  • Evolution of the lesion
• Prognosis of malignant melanoma is determined by the thickness of invasion in the skin, known as Breslow thickness:

  • > 2mm indicates a very poor prognosis
  • <0.76mm has a 98% cure rate
• Sarcoma:

  • Malignant tumour arising from mesenchymal tissue
  • Mesenchyme: loosely organized, mainly mesodermal embryonic tissue which develops into connective and skeletal tissues, including blood and lymph
• Types of sarcoma include:

  • Rhabdomyosarcoma (skeletal muscle)
  • Leiomyosarcoma (smooth muscle)
  • Osteosarcoma (bone)
  • Chondrosarcoma (cartilage)
  • Angiosarcoma (blood vessel)
  • Kaposi sarcoma (blood/lymph vessel)
  • Malignant schwannoma (nerves)
  • Liposarcoma (fat)
• Sites of sarcomas can be in limbs, trunk, abdomen, or anywhere. They typically present as deep tissue lumps or metastases
• Aetiology of sarcomas can include exposure to chemicals like herbicides/pesticides, asbestos, inherited factors, post-radiotherapy, and immunodeficiency
• Inherited susceptibility to sarcomas can be seen in conditions like Li Fraumeni Syndrome and Von Recklinghausen disease
• Prognosis of sarcomas is influenced by stage, type, size, site, grade, and completeness of excision
• Treatment of sarcomas involves wide local excision, radiotherapy, and sometimes chemotherapy. Targeted therapies like Imatinib may be used for specific types of sarcomas
• Neuroendocrine neoplasms are tumors with endocrine function and neural features. They can be malignant, highly aggressive and lethal (small cell carcinoma), less aggressive (carcinoid tumor), or benign
• Small cell carcinoma usually arises in the lung, is a high-grade neuroendocrine neoplasm, and often produces ectopic hormones like ACTH. It is positive for neuroendocrine markers and presents with small cells with specific characteristics
• Carcinoid tumors are low-grade neuroendocrine neoplasms that can arise in various locations like the appendix, ileum, bronchus, or anywhere. They are biologically malignant but may not metastasize for many years
• Carcinoid syndrome develops due to the effects of serotonin, causing symptoms like facial flushing, diarrhea, bronchospasm, and pulmonary stenosis
• Biochemical diagnosis of carcinoid syndrome involves measuring increased urinary 5-HIAA, a breakdown product of serotonin
• Multiple Endocrine Neoplasm (MEN) is a genetically inherited condition where patients have more than one neuroendocrine neoplasm
• Germ cell tumors can include seminoma, dysgerminoma, teratoma, choriocarcinoma, yolk sac tumor, embryonal carcinoma, and mixed tumors. They arise from cells that can recapitulate the 3 germ cell layers
• Seminoma is a malignant germ cell tumor that typically occurs in males aged 20-40 and has a characteristic lymphocytic host response. It usually does not require chemotherapy unless in late stages
• Teratoma can be malignant in adult testis and benign in adult ovary. Malignancy is due to the presence of immature or malignant components in the tumor at histology
• Choriocarcinoma is a highly aggressive germ cell tumor derived from trophoblasts that produces HCG
• Germ cell tumors can be detected through tumor markers like alpha-fetoprotein, HCG, and others
• Prognosis of germ cell tumors has been improved with chemotherapy, allowing for long-term follow-up with regular analysis of serum tumor markers
• Embryonic tumors are aggressive childhood tumors consisting of one embryonal-like cell. They can involve various organs like the neural tissue, kidney, retina, and cerebellum