In ALK-positive ALCL, a portion of the ALK gene has merged with another site on the same or different chromosome to form a chimeric gene consisting of part of the new site and part of the ALK gene coding for ALKs activity. This chimeric gene overproduces a fusion protein with excessive ALK activity. ALK is a serine/threonine-specific protein kinase that activities PI3K/AKT/mTOR, Ras-activated ERKs, Janus kinase-activated STAT proteins, and other cell signaling pathways as well as the expression of various genes by epigenetic mechanisms. Activations of these signaling pathways and genes may stimulate cell growth, proliferation, survival, and/or other behaviors that promote malignancy. ALK-negative ALCL, while not involving ALK translocations, has, in a variable percentage of cases, various translocations, rearrangements, and mutations that may contribute to its development.pcALCL and BIA-ALCL are far less aggressive lymphomas that tend to be localized to one or a very few sites. pcALCL presents as a single or, less commonly, multifocal skin papules or tumors that typically are limited to the dermis without infiltrating to the subcutaneous tissues or spreading to other sites. Its neoplastic cells may contain some gene translocations including, in very rare cases, ones with the ALK gene that are similar to those in ALK-positive ALCL. BIA-ALCL is caused by and develops around a breast implant. It typically presents many years after the surgical implantation as a deformation, textural change, and/or pain emanating in the area around implanted breast. In most cases, the disease is localized to the involved breast.
Chemotherapy treatments containing both anthracycline and etoposide were associated with superior overall survival rates (3- and 5-years of 76% and 69%, respectively) compared to chemotherapy treatment regiments containing an anthracycline but not etoposide (3- and 5-year overall survival rates of 56% and 44%, respectively). Progression-free survival rates with the latter two types of chemotherapy treatment regimens were not appreciably different. Primary cutaneious anaplastic large cell lymphoma
Signs and symptoms
pcALCL is the second most common lymphoma in the category of Cutaneous T cell lymphoma cutaneous T cell lymphomas that includes lymphomatoid papulosis, various borderline CD30-positive cutaneous T cell lymphomas, and mycosis fungoides. The median age at diagnosis for pcALC is 61 years. The disease has a male predominance and appears to be more common in Caucasian populations. Individuals with pcALCL typically present with reddish masses that initially appear in the skin or, much less frequently, the lymph nodes or various organs. These masses are nodules or tumors that are often ulcerated, greater than 2 cm in diameter, and localized to a single site. In 20% of cases, however, they occur in multiple sites. In about 10% cases followed for many years, pcALCL presenting as skin lesions progresses to extracutaneous sites, mainly to regional draining lymph nodes. Over these same long periods, however, the diseases lesions partially regress in about 50% of cases but then relapse in about 40% of cases. Diagnosis
pcALCL lesions exhibit large malignant T-cells or null cells (i.e. cells lacking many T-cell receptor proteins) with "Hallmark" cell features of anaplasia, pleomorphism, and kidney- and horse shaped-nuclei.