Oncology Case Discussions


CASE 3: Squamous Cell Carcinoma of Lung


Clinical History:

You see a 63 year-old man in the outpatient clinic. He has no health insurance and has not had regular medical follow-up for some time. He has noted a "lump" in his neck for the past two months. It has grown from marble-sized to the size of a small golf ball during that time. He feels well, with no weight loss, chills, fever or night sweats. He has a mild "smoker's cough" that has been unchanged for the past few years. His exercise tolerance is unchanged at two flights of stairs. He is a heavy smoker (80 pack-years). Aside from minor surgical procedures, he has no significant past medical history. You examine the patient. He has nicotine-stained fingers. Lung exam shows his chest to be mildly hyperexpanded. There are occasional diffuse wheezes over the lung fields. There is no dullness to percussion. There is a 2.5 cm diameter fixed, gritty-feeling, non-tender mass at the base of the right sternocleidomastoid muscle, just above the clavicle. The remainder of the physical examination, including a screening neurological exam, is unremarkable.

Findings:

The chest xray reveals a large mass lesion in the right chest (image 3.1), confirmed by the CT scan (image 3.2). The appearance is consistent with a lung primary. The FNA of the mass yields irregular cells with orange cytoplasm and dark, angular nuclei typical for squamous cell carcinoma (image 3.3). The microscopic appearance at high magnification (image 3.4) shows pink polygonal cells with some intercellular bridges typical for a squamous cell carcinoma.

Questions:

  1. With the patient's heavy smoking history, you suspect that he has lung cancer with a metastasis to a lymph node in the neck. However, like any good medical student, you wish to broaden your differential diagnosis. What other cancers could produce metastases in this location?

    2. A rational approach to this problem is based upon: 1) the anatomical location of structures that have lymph node drainage into the neck, and 2) the clinical/epidemiologic incidence of cancer in these structures. Likely suspects for primary cancers include: lung, upper aerodigestive tract, breast (for women), thyroid, and gastrointestinal tract. Lymphoma is also a possibility.

  2. The chest radiograph shows a 5 cm mass involving the right hilum. There appears to be some nodular fullness at the right side of the mediastinum consistent with enlarged nodes in this area. There are no effusions or consolidation. Lung cancer seems likely. What do you do next?

    3. A tissue diagnosis needs to be established PRIOR to staging. This clinical representation (but not the chest radiograph) is also consistent with a primary squamous cell carcinoma of the head/neck region (such as larynx) with a nodal metastasis.

  3. Fine needle-aspiration cytology of the neck mass shows malignant cells to be present. By immunohistochemical staining, the cells are positive for cytokeratins. Other special immunohistochemical stains, including neuron-specific enolase (NSE), leukocyte common antigen (LCA), thyroglobulin, prostate specific antigen (PSA), and vimentin are all negative. What type of cancer is this? Is it primary or metastatic? What do the special stains tell you?

    4. These stains are strongly suggestive of metastatic squamous cell carcinoma of the lung. Cytokeratins are typical of epithelial malignancies, including squamous cell carcinomas, which are usually related to smoking. NSE is more characteristic for small cell carcinomas. LCA is seen with malignant lymphomas. Thyroglobulin can be positive with thyroid carcinomas. The PSA is specific for prostatic adenocarcinoma. Other markers can be used in specific situations, particularly on excisional biopsy specimens, and may include: estrogen/progesterone receptors for breast cancers, S-100 and/or HMB-45 and/or melanA for melanomas, and CEA for GI tract adenocarcinomas.

  4. What other studies would you obtain to stage this patient? Based on the information provided above, what is his clinical stage?

    5. The patient has already been diagnosed with metastatic disease, and therefore an extensive radiologic evaluation is not necessary.

  5. What types of treatments would you offer this patient?

    6. No treatment has been shown to prolong lifespan more than a few months for patients with metastatic squamous cell carcinoma of the lung. The potential choices are: 1) observation only, 2) palliative radiation therapy, and 3) palliative chemotherapy.