Poorly differentiated squamous cell carcinoma is an aggressive form of skin cancer originating from squamous cells in the outer layer of the skin. This cancer is characterized by its atypical cellular appearance under a microscope, indicating a potentially faster-growing malignancy. Understanding its characteristics and behavior is important for managing this cancer.
What Poorly Differentiated Means
The term “differentiation” in cancer refers to how much cancer cells resemble normal, healthy cells from which they originated. When cells are “poorly differentiated,” they appear highly abnormal and have lost most of the features of normal squamous cells. These cells lack the typical organization and structure seen in healthy tissue.
Poorly differentiated cells are aggressive. This lack of resemblance suggests rapid growth and a higher likelihood of spread. Tumors with poorly differentiated cells are assigned a higher grade, indicating a greater potential for aggressive behavior and a poorer prognosis compared to well-differentiated or moderately differentiated cancers. This characteristic influences how the cancer might behave and how medical professionals approach its treatment.
Where It Appears and How It’s Found
Poorly differentiated squamous cell carcinoma commonly appears on sun-exposed areas of the body, such as the face, ears, lips, scalp, neck, hands, and arms. However, it can also develop in areas not typically exposed to the sun, including mucous membranes or regions of chronic inflammation. In individuals with darker skin tones, SCCs may occur more frequently in non-sun-exposed areas.
Symptoms can vary, but include a scaly or crusty lump that grows over weeks to months, which may or may not have a crust. The lesion might appear as a red, scaly patch, an open sore that does not heal, or an elevated growth with a central depression. It can also manifest as a firm nodule or a new sore on an old scar. If untreated, the cancer can break down, ulcerate, ooze, and potentially invade adjacent structures like bone or muscle.
Diagnosis begins with a clinical examination of any suspicious spots. If cancer is suspected, a skin biopsy is performed, where a small tissue sample is removed for microscopic examination. Pathological analysis determines the type of cancer and its differentiation grade. Imaging tests, such as CT scans or MRIs, may be used to assess the tumor’s size, depth, and whether it has spread to lymph nodes or other organs. Accurate staging is important for guiding treatment decisions.
Approaches to Treatment
Treatment for poorly differentiated squamous cell carcinoma often involves a multi-modal approach, with surgery as a primary method. Mohs micrographic surgery is frequently recommended for high-risk SCCs, including those that are poorly differentiated, large, or located on cosmetically sensitive areas like the face, ears, or lips. This technique involves removing thin layers of cancerous tissue one at a time, examining each layer under a microscope until no cancer cells remain, and preserving healthy tissue. Wide local excision is another surgical option, removing the tumor along with a margin of surrounding healthy tissue.
Radiation therapy is often used as an adjuvant treatment after surgery to destroy any remaining cancer cells and reduce recurrence risk. It can also be a primary treatment option for tumors difficult to remove surgically or for patients unable to undergo surgery. Radiation therapy can be delivered through external beams or radioactive implants.
For advanced or metastatic disease, systemic treatments like chemotherapy, targeted therapy, and immunotherapy may be considered. Chemotherapy uses powerful medicines to kill cancer cells throughout the body, though its response rate can be relatively low for advanced cutaneous SCC. Targeted therapies focus on specific molecules involved in cancer cell growth, such as EGFR inhibitors, which may be overexpressed in SCC. Immunotherapy, including checkpoint inhibitors like cemiplimab and pembrolizumab, helps the body’s immune system recognize and attack cancer cells, and has shown promising results for advanced cases not amenable to surgery or radiation.
Outlook and Ongoing Care
The prognosis for poorly differentiated squamous cell carcinoma is influenced by its aggressive nature and tendency for rapid growth and spread. Early detection and timely, appropriate treatment significantly improve outcomes. Most SCC cases, when found early, have a high survival rate.
Long-term management emphasizes regular follow-up appointments, typically including full skin checks and examination of regional lymph nodes, to monitor for recurrence or new lesions. Patients are advised on the importance of sun protection, including avoiding excessive sun exposure, using sunscreen, and wearing protective clothing. Performing regular skin self-exams is a recommended part of ongoing care to identify changes early.