Squamous cell carcinoma of the skin laboratory findings
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Squamous cell carcinoma of the skin Microchapters |
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Differentiating Squamous cell carcinoma of the skin from other Diseases |
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Aditya Govindavarjhulla, M.B.B.S. [2], Raviteja Guddeti, M.B.B.S. [3]
Overview
Squamous cell carcinoma of the skin is most often caused by long term exposure to the sun, and other certain risk factors. No specific laboratory tests are indicated for the diagnosis, as physical exam and biopsy are the primary means of diagnosis. Histopathological evaluation of the biopsy specimen stands out to be the most important diagnostic test.
Laboratory tests
No specific laboratory tests are required for the diagnosis of squamous cell carcinoma. Routine blood tests are performed as part of the complete evaluation, including a complete blood count and serum electrolytes. Liver function tests will help to determine if there is metastatic spread to the liver. Blood gas analysis and pulmonary function testing may be helpful in cases of SCC of lungs, in addition to other imaging studies. Another important test to assess for paraneoplastic syndrome is a serum calcium, as SCC of the lungs can cause hypercalcemia. For this reason, blood levels of parathormone should also be obtained if SCC of the lung is suspected.
Histopathological examination confirms diagnosis and aids in the staging of the disease. Histopathological evaluates in detail the following characteristics of the specimen;
- Invasion
- Differentiation
- Depth
The various types of biopsy that may be obtained includes shave, punch, and excisional biopsies. The sample may be obtained at a physician's office under local anesthesia. The type of biopsy method chosen is based upon the size of lesion.
- For smaller lesions in easy accessible region of the body, an excisional biopsy is preferred. This may be therapeutic as well as diagnostic.
- For lesions which are large and for which the cosmetic appearance may be of concern, a punch biopsy is advisable. Further treatment is based upon the results of histopathological evaluation.
- A shave biopsy is seldom recommended in cases where the lesion is suspected to be malignant.
Important principles to consider when taking a sample for biopsy.
- A full thickness biopsy should be taken to best evaluate the true depth of the lesion and extent of invasion. Depth of the lesion is an important determinant in the prognosis and staging of cancer.[1]
- The biopsy specimen should also include samples of normal tissue as a comparison.
- Large lesions require a thorough sample that will adequately assess the entirity of the lesion.
Toluidine Blue can be used for early detection of oral lesion of squamous cell carcinoma as an adjunvant. It has got high sensitivity, specificity and accuracy in detecting premalignant lesions. [2]Basic principle of toluidine blue staining is that it doesn't stain mucosa, dye is being easily absorbed by the nuclei of malignant cells and they are clearly seen.
Patients who were found to have regional lymphadeonpathy identified during physical examination or during imaging studies should undergo lymph node biopsy or fine needle aspiration biopsy.
Histological Findings The findings are very important to the physician as it well help him in guiding the next step. The neoplastic cells may demonstrate varying degrees of squamous differentiation and atypia.
- The most conspicuous finding is keratin pearls( well formed desmosome attachments and intracytoplasmic bundles of keratin tonofilaments)
- Depending on the histology it can be graded into three
- Well differentiated : nuclei which are more normal, abundant cytoplasm & extracellular keratin pearls
- Poorly differentiated : High degree of nuclear atypia,greater nuclear cytoplasmic ration and very less keratinization. It at times due to poor differentiation mimics mesenchymal tumors.Poorly differentiated carcinoma has higher rates of metastasis and high rates of invasion into surrounding tissues.
- Moderately differentiated : This type of hsiolgy had a look in between these two types.
- Squamous cell carcinoma in situ - it has full thick atypia of squamous cells(including surfaces) without invading the basement membranes.
- Invasive carcinomas have most of the times inflammation when it invades the surrounding tissues.
Sputum Cytology SCC of lungs which are centrally located and exfoliated, the cells of that can be seen in sputum cytology. It is easy,quick and economical.But it has high false negative rate. Accuracy depends a lot on its storage, collection, number of samples, location of tumor. Sputum cytology has low false negative which account gives us a good clue for further investigations. Further studies can be done by collecting samples from bronchoscopy.
References
- ↑ Brantsch KD, Meisner C, Schönfisch B, Trilling B, Wehner-Caroli J, Röcken M, et al. Analysis of risk factors determining prognosis of cutaneous squamous-cell carcinoma: a prospective study. Lancet Oncol. Aug 2008;9(8):713-20
- ↑ name="pmid22259809">Rahman F, Tippu SR, Khandelwal S, Girish KL, Manjunath BC, Bhargava A (2012). "A study to evaluate the efficacy of toluidine blue and cytology in detecting oral cancer and dysplastic lesions". Quintessence Int. 43 (1): 51–9. PMID 22259809. Unknown parameter
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