Receiving a lymphoma diagnosis can be a frightening and overwhelming experience. This complex group of blood cancers comes in many different forms, each with its own unique characteristics, treatments, and prognosis. One rare but important type is Anaplastic Large Cell Lymphoma (ALCL). ALCL is a type of non-Hodgkin lymphoma that arises from a mature type of immune cell called a T-lymphocyte. While a cancer diagnosis is always serious, it is crucial for newly diagnosed patients and their families to understand that ALCL, particularly certain subtypes, is a highly treatable and often curable cancer with modern chemotherapy regimens. A correct and detailed diagnosis is the first and most critical step on the path to effective treatment and recovery.

Anaplastic Large Cell Lymphoma is a cancer of the lymphatic system. The lymphatic system is a vital part of the body’s immune network, composed of lymph nodes, spleen and other tissues. Lymphoma occurs when lymphocytes, a type of white blood cell, begin to grow and multiply uncontrollably.

ALCL is specifically a type of T-cell non-Hodgkin lymphoma. This distinguishes it from the more common B-cell lymphomas. The name itself provides clues to its identity:

• Anaplastic: This is a pathological term meaning the cancer cells are large and appear very undifferentiated or “primitive” under a microscope.
• Large Cell: The individual cancer cells are significantly larger than normal lymphocytes.
• Lymphoma: A cancer of the lymphocytes.

There are four main, distinct types of ALCL, each with a different clinical behavior and prognosis:

1. ALK-Positive, Systemic ALCL: The cancer cells have a specific genetic abnormality involving the ALK gene. This type is more common in children and young adults and has a very good prognosis.
2. ALK-Negative, Systemic ALCL: The cancer cells do not have the ALK gene abnormality. This type is more common in older adults and can be more challenging to treat.
3. Primary Cutaneous ALCL: This is a slow-growing (indolent) form of ALCL that is confined only to the skin. It has an excellent prognosis.
4. Breast Implant-Associated ALCL (BIA-ALCL): This is a rare form of ALCL that develops not in the breast tissue itself, but in the scar tissue capsule that forms around a breast implant, typically years after surgery.

In my experience, ALCL can be deceptive. It sometimes mimics infections or benign swellings before biopsy reveals its aggressive nature.

The underlying cause of ALCL is the acquisition of genetic mutations within a T-lymphocyte that cause it to lose its normal growth controls and divide uncontrollably.

In the case of ALK-positive ALCL, the specific cause is a well-understood genetic accident called chromosome translocation.

• A helpful analogy is to think of your 23 pairs of chromosomes as 23 pairs of instruction manuals.
• In ALK-positive ALCL, it is as if during a “photocopying” error in a developing T-cell, the back cover of Manual #2 is accidentally ripped off and gets fused to the front cover of Manual #5.
• This faulty binding brings together two completely separate genes: the ALK gene from chromosome 2 and the NPM gene from chromosome 5.
• The resulting hybrid gene creates a new, faulty protein called NPM-ALK. This protein acts like a permanently stuck accelerator pedal, constantly sending powerful signals that tell the T-cell to grow and divide without stopping. This single, specific genetic event is the direct driver of ALK-positive ALCL.

In ALK-negative ALCL, the causes are more varied, involving different mutations in other genes that also lead to uncontrolled T-cell growth. In BIA-ALCL, it is thought that chronic inflammation related to the textured surface of some implants may play a role in a genetically susceptible person.

Clinically, the exact cause remains unclear, but I’ve seen strong associations with genetic mutations involving ALK (anaplastic lymphoma kinase), particularly in younger patients.

With the exception of BIA-ALCL, there are no known preventable risk factors for developing ALCL. It is not contagious and cannot be passed from person to person. For most people, it is believed to be a random genetic event that occurs by chance.

• Systemic ALCL can affect people of any age, but the ALK-positive form is more common in the first three decades of life, while the ALK-negative form is more common in adults over 60.
• Primary Cutaneous ALCL also typically affects adults.
• Breast Implant-Associated ALCL is a rare complication linked specifically to having breast implants, particularly those with a textured surface.

Clinically, I’ve seen breast implant-associated cases develop years after implant surgery, typically presenting with swelling, a mass, or fluid buildup near the implant capsule.

Signs and symptoms of ALCL depend on the specific disease type.

Symptoms of Systemic ALCL (Both ALK-Positive and ALK-Negative)

• Painless Swelling of a Lymph Node: This is the most common first sign. A person may notice a persistent, painless lump in the neck, armpit, or groin.
• “B Symptoms”: This is a classic triad of systemic symptoms that are common in aggressive lymphomas.
  • Unexplained Fever that can come and go.
  • Drenching Night Sweats that may require changing clothes or bedding.
  • Unintentional Weight Loss of more than 10% of body weight over six months.
• Extranodal Involvement: ALCL frequently affects sites outside of the lymph nodes. This can include the skin (causing rashes or nodules), bones (causing pain), or lungs (causing a cough or shortness of breath).

Symptoms of Primary Cutaneous ALCL

Symptoms are limited to the skin.

• The appearance of one or more red, raised nodules or tumors on the skin.
• These lesions may grow, break open and ulcerate, and then sometimes spontaneously regress before new ones appear.

Symptoms of Breast Implant-Associated ALCL

This typically presents years after the initial implant surgery.

• Swelling or Pain in one breast.
• A lump or mass near the implant.
• The most common sign is a large fluid collection (seroma) that develops around the implant.

Clinically, I always consider ALCL in patients with unexplained lymphadenopathy and systemic symptoms especially if CD30 positivity is found on biopsy.

A diagnosis of ALCL is suspected based on symptoms like a swollen lymph node. The definitive diagnosis always requires a biopsy.

1. Biopsy: The gold standard for diagnosing any lymphoma is an excisional lymph node biopsy. This is a surgical procedure where the entire swollen lymph node is removed. A fine-needle aspiration is not sufficient. For cutaneous or BIA-ALCL, a biopsy of the affected skin or capsule tissue is taken.
2. Pathology and Immunohistochemistry (IHC): The tissue sample is sent to a pathologist, who examines it under a microscope. To make a definitive diagnosis of ALCL, they will perform special stains called immunohistochemistry.
   • A key finding is that the large cancer cells will be strongly positive for a marker called CD30.
   • The most critical stain is for the ALK protein. If the cells stain positive for ALK, it confirms a diagnosis of ALK-positive ALCL. If they are negative, it is ALK-negative ALCL. This distinction is vital as it determines the prognosis.
3. Staging: Once the diagnosis is confirmed, a series of tests are done to determine the stage of the disease (i.e., how far it has spread). This typically involves:
   • Blood tests, including a complete blood count.
   • A PET/CT scan, which is a highly sensitive imaging test that can detect lymphoma throughout the body.
   • A bone marrow biopsy may also be performed.

In my experience, immunohistochemistry and molecular testing are crucial for subtyping (ALK-positive vs. ALK-negative), as treatment and prognosis vary significantly.

Treatment of ALCL is highly effective and depends entirely on the specific type of the disease.

Treatment for Primary Cutaneous ALCL

Because this is a slow-growing disease confined to the skin, treatment is often local.

• Surgery to remove a single lesion.
• Radiation therapy to treat one or more lesions in a specific area.
• For more widespread skin disease, systemic therapies may be used. The prognosis is excellent.

Treatment for Breast Implant-Associated ALCL

• The primary and often curative treatment is surgery. This involves removing the breast implant and, crucially, the entire surrounding scar tissue capsule.
• For early-stage disease that is confined to the capsule, surgery alone is often all that is needed.
• If the disease is more advanced, chemotherapy may be required.

Treatment for Systemic ALCL (ALK-Positive and ALK-Negative)

This is an aggressive lymphoma requiring intensive, multi-agent chemotherapy. However, it is also a cancer that responds very well to this treatment.

• Combination Chemotherapy: The standard treatment for decades has been a combination of several chemotherapy drugs, most commonly a regimen known as CHOP (Cyclophosphamide, Doxorubicin, Vincristine, and Prednisone) or a similar combination.
• Targeted Therapy with Brentuximab Vedotin: A major advance in treatment is the use of a targeted drug called brentuximab vedotin. This is an antibody-drug conjugate. The antibody part seeks out the CD30 marker on the surface of the ALCL cells, and then it delivers a potent chemotherapy agent directly to the cancer cell, like a “smart bomb.” It is now often combined with chemotherapy in the front-line setting and has significantly improved cure rates.
• Stem Cell Transplant: For patients who relapse after initial chemotherapy, a high-dose chemotherapy followed by an autologous stem cell transplant (using the patient’s own stem cells) or an allogeneic stem cell transplant (using a donor’s stem cells) may be an option.

Prognosis

• The prognosis for ALK-positive ALCL is very good. With modern chemotherapy regimens, the long-term cure rate is very high, often exceeding 80%.
• The prognosis for ALK-negative ALCL is more challenging and generally less favorable than the ALK-positive type, but many patients can still be cured.

Clinically, I tailor treatment intensity to subtype and patient age, BIA-ALCL,  when caught early, often responds well to surgical implant removal without systemic therapy.

A diagnosis of Anaplastic Large Cell Lymphoma is a serious and challenging event, but it is one that should be met with significant hope. This rare T-cell lymphoma is a highly treatable and often curable disease. A correct and detailed diagnosis, made by an expert pathologist and including the critical distinction between ALK-positive and ALK-negative disease, is the key to understanding the prognosis and planning the most effective treatment. With modern, aggressive combination chemotherapy regimens, now often including powerful targeted drugs like brentuximab vedotin, the majority of patients with systemic ALCL can be cured of their disease and look forward to a healthy future.

1. Leukemia & Lymphoma Society (LLS). (n.d.). Anaplastic Large Cell Lymphoma. Retrieved from https://www.lls.org/lymphoma/non-hodgkin-lymphoma/nhl-subtypes/anaplastic-large-cell-lymphoma
2. National Cancer Institute (NCI). (2024). Adult Non-Hodgkin Lymphoma Treatment (PDQ®)–Patient Version. Retrieved from https://www.cancer.gov/types/lymphoma/patient/adult-nhl-treatment-pdq
3. Lymphoma Research Foundation. (n.d.). Anaplastic Large Cell Lymphoma. Retrieved from https://lymphoma.org/aboutlymphoma/nhl/alcl/