rare

Adrenocortical carcinoma is a rare, aggressive cancer of the adrenal gland that often over-produces hormones. Surgery is the only cure, mitotane is the one drug specific to it (with real toxicity), and chemotherapy or immunotherapy help only a minority.

Ampullary cancer, a biliary tract cancer, starts where the bile and pancreatic ducts empty into the small bowel. Because it blocks bile flow early it is often caught while still removable, and the Whipple operation cures a good share of patients. Tumours come in two flavours, intestinal-like and pancreas-like, and chemotherapy is increasingly chosen by which one the pathologist sees.

Rare tumours of the appendix that range from slow mucin-producing growths that fill the abdomen (pseudomyxoma peritonei) to aggressive adenocarcinomas. The slow forms are treated by extensive surgery with heated chemotherapy in the abdomen; the fast ones like colon cancer.

Blastic plasmacytoid dendritic cell neoplasm is a rare aggressive leukaemia-like blood cancer of dendritic-cell precursors, a few hundred US cases a year, that often first appears as bruise-like skin lesions. Two CD123-directed drugs, tagraxofusp and pivekimab sunirine, are the first targeted therapies; allogeneic transplant in first remission is still the only route to long-term control.

Chordoma is a slow-growing bone cancer (a sarcoma) of the skull base and spine that arises from leftover embryonic notochord cells. Complete surgery followed by high-dose proton or carbon-ion radiotherapy controls most tumours, and the whole disease depends on a single transcription factor, brachyury, which vaccines and degraders are now trying to hit.

Chronic myelomonocytic leukaemia and its relatives are bone-marrow cancers that behave partly like myelodysplasia (poorly made blood cells) and partly like a proliferative disease (an excess of monocytes or platelets). Hypomethylating agents produce responses in a minority and stabilise counts in more, transplant can cure the fit, and RAS-pathway and JAK inhibitors are in trials.

Desmoid tumours are locally aggressive growths of fibroblast-like cells, classed with soft-tissue sarcomas, driven by WNT mutations, that never spread to distant organs but can invade nerves, bowel and muscle. Many stop growing or shrink on their own, so watching first is standard; if they progress, the gamma-secretase inhibitor nirogacestat, approved in 2023, shrinks tumours and relieves pain.

Epithelioid sarcoma is a rare soft tissue cancer that has lost a gene brake called SMARCB1, leaving it dependent on the enzyme EZH2. Surgery cures localised tumours. The EZH2 inhibitor tazemetostat, the first epigenetic drug approved for a solid tumour, was approved in 2020 and withdrawn worldwide in March 2026 after secondary blood cancers in a lymphoma trial, so there is no targeted drug today.

Histiocytoses are diseases in which immune scavenger cells build up in bone, heart, brain, kidneys and skin. They used to be treated as inflammatory conditions with steroids and interferon. The discovery that most carry mutations in the same growth pathway as melanoma turned them into targetable cancers: BRAF and MEK inhibitor pills now produce responses in nearly every treated patient.

Extragonadal germ cell tumours are the same cancers as testicular germ cell tumours but arising in the midline of the body, most often the chest or the back of the abdomen. Seminomas are highly curable with chemotherapy; non-seminomas of the chest are the hardest germ cell tumours to cure and are treated with intensive chemotherapy followed by surgery.

Gallbladder cancer is a biliary tract cancer of the bile-storing sac under the liver, most often found by chance when the gallbladder is removed for stones. Caught early, a second operation to clear the liver bed and nodes can cure it; for advanced disease, chemotherapy now comes with an immunotherapy partner, and HER2-directed antibodies help the subset whose tumours over-express HER2.

Cancers that grow from placental tissue after a pregnancy. They make a hormone (hCG) that acts as a perfect blood test, and they were the first solid cancer ever cured by chemotherapy. Immunotherapy now rescues the few that resist drugs.

People living with HIV have a raised risk of aggressive lymphomas, driven by immune suppression and viruses such as Epstein-Barr virus. The transformation of the last two decades is that, with antiretroviral therapy continued through treatment, these lymphomas are treated with the same full-dose chemotherapy and antibody regimens as in anyone else, with similar chances of cure.

IMT is a rare tumour, grouped with the sarcomas, of spindle cells mixed with inflammatory cells, most often in the lung or abdomen of children and young adults. Surgery cures most, and about half carry an ALK gene fusion, so the ALK-blocking pill crizotinib is approved for those that cannot be removed, one of the first targeted approvals for a childhood solid tumour.

Men get breast cancer too, usually a hormone-sensitive kind found as a lump near the nipple. It is treated much as in women, with surgery, radiotherapy and tamoxifen, and inherited BRCA2 mutations are found often enough that every man diagnosed is offered genetic testing. The main fix under way is including men in trials so their care stops being borrowed from women.

Merkel cell carcinoma is a rare, fast-growing skin cancer, usually caused by a common virus (Merkel cell polyomavirus) or by sun damage. It was almost untreatable once it spread; PD-1/PD-L1 immunotherapy now gives lasting responses in about half of patients.

The MEN syndromes are inherited faults in a single gene that cause tumours in several hormone glands over a lifetime. Because the gene can be found in childhood, at-risk relatives can be tested, watched and in MEN2 have the thyroid removed before cancer develops; and for MEN2 thyroid cancer that does spread there is now a precise pill, selpercatinib, that blocks the faulty RET protein.

Cancers of the nose and sinuses are a mixed group, from squamous carcinoma to the nerve-derived esthesioneuroblastoma and the aggressive undifferentiated carcinoma SNUC. Surgery through the nose with an endoscope followed by precise radiotherapy has replaced disfiguring open operations, and giving chemotherapy first to see who responds now guides how SNUC is treated.

NUT carcinoma is a fast-growing cancer of the midline of the body driven by a single fused gene, BRD4-NUTM1, that locks cells in an immature state. Chemotherapy and surgery rarely control it for long, but drugs that block the BET proteins the fusion depends on have produced responses and are the focus of trials.

Parathyroid carcinoma is a cancer of the glands that control blood calcium, seen in a few people per ten million a year; most of its harm comes from dangerously high calcium rather than spread. Removing the tumour intact at the first operation gives the best chance of cure, and cinacalcet and bone-protecting drugs control calcium when it cannot be removed.

Penile cancer is a squamous skin-type cancer, about half of it caused by HPV. Caught early it is usually cured with organ-sparing surgery that has replaced amputation, and HPV vaccination and circumcision prevent it; the hard cases are those with lymph-node spread, where cisplatin-based chemotherapy plus surgery and now immunotherapy are being tested in the InPACT trial.

Pheochromocytomas and paragangliomas are tumours of adrenaline-producing tissue that cause dangerous blood pressure surges. Surgery after careful blood-pressure blockade cures most, genetic testing finds an inherited cause in nearly half, and for the minority that spread there are now radioactive drugs that home to the tumour and, since 2025, the first oral targeted pill, belzutifan.

Pituitary tumours are usually benign growths of the hormone gland at the base of the brain that cause trouble by overproducing hormones or pressing on the optic nerves. Prolactin-producing tumours melt away with a tablet, most others are cured by surgery through the nose, and the rare aggressive ones respond to the chemotherapy drug temozolomide.

After an organ or stem cell transplant, the drugs that stop rejection also stop the immune system from policing Epstein-Barr virus, and infected B cells can grow into a lymphoma. The first move is to ease the immunosuppression; then the antibody rituximab, chemotherapy if needed, and, newest of all, off-the-shelf virus-specific T cells that restore the missing immune control.

Salivary gland cancers are a family of over 20 rare cancers, each with its own behaviour and often its own gene fusion. Surgery and radiation treat most; drug therapy is now chosen by the specific subtype, from anti-HER2 or anti-androgen drugs to NTRK inhibitors.

Sarcomas are dozens of rare cancers of bone and connective tissue. GIST was the first solid tumour cured-in-practice by a targeted pill; synovial sarcoma got the first TCR-T therapy.

Cancers of the small intestine are rare and often found late because the small bowel is hard to see and symptoms are vague. Surgery cures early disease, chemotherapy borrowed from bowel cancer helps after surgery and in advanced disease, and a large minority of tumours have a repair defect that makes them respond well to immunotherapy.

Systemic mastocytosis is a clonal disease of mast cells, the immune cells that release histamine; almost every case is driven by a single mutation in the KIT gene. Precise KIT-blocking pills now shrink the mast cell burden, ease symptoms and, in the aggressive forms, prolong life. Most patients have the indolent form, where the goal is controlling symptoms and preventing anaphylaxis.

TGCT is a benign but destructive tumour of the joint lining, classed with soft-tissue sarcomas, in which a few cells carrying a CSF1 gene fusion recruit a crowd of normal immune cells that eat away at the joint. Surgery cures most localised cases, and for diffuse or recurrent disease two pills that block the CSF1 receptor, pexidartinib and vimseltinib, shrink tumours and restore joint function.

Thymoma and thymic carcinoma are rare tumours of the thymus gland in the chest. Thymomas grow slowly, often cause autoimmune diseases such as myasthenia gravis, and are usually cured by surgery; thymic carcinomas behave like other aggressive cancers and have few effective drugs.

Urethral cancer grows in the tube that carries urine out of the body, with fewer than one case per million people a year. With no randomised trials, it is treated by borrowing from bladder, anal or vulvar cancer depending on cell type and location; chemotherapy with radiotherapy before or instead of surgery lets more patients keep their organs.

Uterine sarcomas are rare cancers of the muscle and supporting tissue of the womb, distinct from the far commoner endometrial cancer. Removing the uterus intact is the main treatment and is followed by observation for stage I disease; low-grade stromal sarcomas respond to hormone-blocking pills, while advanced leiomyosarcoma is treated with doxorubicin and trabectedin.

A melanoma inside the eye that is biologically unrelated to skin melanoma: different mutations, no response to standard immunotherapy, and a tendency to spread to the liver years later. Tebentafusp is the first drug ever to extend survival in the metastatic disease.

Primary vaginal cancer is rare and mostly caused by HPV, the virus behind cervical cancer. It is treated like cervical cancer, with weekly cisplatin alongside external and internal radiotherapy, which controls most tumours while preserving the organ; HPV vaccination and cervical screening, which also detects vaginal precursors, are steadily reducing it.

Vascular tumours range from angiosarcoma, an aggressive cancer of blood vessel lining cells, to the slow-growing EHE and the infant tumour KHE. Angiosarcoma responds to paclitaxel and, in the sun-damaged scalp form, to immunotherapy; EHE and KHE depend on growth signals that the mTOR blocker sirolimus quiets, and EHE without symptoms is watched.