Basaloid squamous cell carcinoma seminar

basaloid squamous cell carcinoma seminar

1. BASALOID SQUAMOUS CELL CARCINOMA . Dr SURYAGOPAN .P

2. INTRODUCTION Basaloid squamous cell carcinoma (BSCC) as defined by the World Health Organization is an aggressive, high-grade, variant of squamous cell carcinoma (SCC) composed of both basaloid and squamous components. It is a recently described squamous cell carcinoma varient that arise primarily in the upper aerodigestive tract, with a prediliction for the larynx, hypopharynx and tongue base.

3. Basaloid squamous cell carcinoma is a rare variant of squamous cell carcinoma with more than 200 cases, which have been published since its first description in 1986 by Wain et al .

4. ETIOLOGY Etiology and pathogenesis of basaloid squamous cell carcinoma is similar to conventional squamous cell carcinoma. Most patients have a long history of smoking and alcohol drinking. In some cases there was a history of previous radiation to the head and neck region . Both represent independent risk factors for the development of squamous cell carcinoma.

5. Smokeless tobacco and other exogenous carcinogens such as occupational, environmental and nutritional factors may also play role in the pathogenesis of this cancer. EBV was detected in few cases using in situ hybridization technique from nasopharyngeal sites. Recent studies detected a higher frequency of HPV and HSV in basaloid tumors than in conventional squamous cell carcinomas of the head and neck.

6. CLINICAL FEATURES Basaloid squamous cell carcinoma tends to occur in persons 40 to 85 years of age. It occurs more commonly in males than in females. The lesion clinically appears as a fungating mass or ulcer and may be painful or interfere with swallowing. Approximately two- third of cases are diagnosed at an advanced clinical stage.

7. HISTOPATHOLOGIC FEATURES As its name connotes basaloid squamous cell carcinoma has two microscopic components. The first is a superficial, well differentiated or moderately differentiated squamous cell carcinoma, often with surface ulceration, multifocal origin and areas of carcinoma in situ. The second deeper component is an invasive basaloid epithelium arranged in islands, cords and gland like lobules.

8. This deeper tumour often shows palisading of peripheral cells, central necrosis and occasional squamous differentiation. The interface between the two components is typically sharp and distinct, but gradual transition from squamous to basaloid cell may be seen ocassionally . The tumour islands are often surrounded by mucoid stroma (basal lamina material)

9. One of the major features of this tumor is that the cells exhibit high nucleocytoplasmic ratio and often have dense hyperchromatic nuclei and comedonecrosis may be seen in these tumor ,

10. Superficial epithelium Underlying connective tissue showing malignant epithelial island LOW POWER VIEW

11. HIGH POWER VIEW Malignant epithelial island Comedo necrosis

12. HIGH POWER VIEW SHOWING MALIGNANT EPITHELIAL ISLANDS Solid island showing biphasic pattern Peripheral tall columnar cells ( Basaloid cells ) Central polygonal cells

13. Differential diagnosis for BSCC Adenoid cystic carcinoma (solid variant) Adenosquamous carcinoma, Basal cell adenocarcinoma , Salivary duct carcinoma and Neuroendocrine carcinoma. Basal cell ameloblastoma

14. Adenoid cystic carcinoma (ACC, solid variant) shows groups of cuboidal cells, with dark nuclei. ACC lacks areas of squamous differentiation, cytologic and nuclear atypia ; antibodies to CD117 react with most ACCs. To differentiate BSCC from ACC (solid variant) we have applied CD117 because ACCs are positive for CD117 whereas BSCCs are not.

15. Adenosquamous carcinoma shows glandular structures lined by basaloid , columnar or mucin -secreting cells. Intracytoplasmic mucin is demonstrated by mucicarmine staining. Basal cell adenocarcinoma shows two forms of cells, usually intermingled with each other-small round cells and large polygonal cells. For the diagnosis of carcinoma, there should be more than 4-5 mitotic figures per 10 high-power fields. Basal cell ameloblastoma shows islands of odontogenic epithelium lined peripherally by cuboidal cells, surrounding central uniform basaloid -appearing cells. There is absence of central comedo necrosis and any squamous component.

16. Immunohistochemistry The immunoprofile of these tumors show consistent positive staining to high molecular weight cytokeratin antibody 34βE12, KL1, and MNF116, and focal staining for vimentin , EMA, CAM5.2, CK7, CEA, S100and GFAP, and negative immunostaining for CK20, chromogranin , synaptophysin , BCL2, and Ber-EP4. Actin staining was positive in the basaloid cells and some cases were positive for CD99.

17. Immunohistochemistry SCC shows positive staining to Cytokeratin (CK) 13 where as basaloid cells in BSCC shows no immunoreactivity . Studies shows higher p53 positivity in BSCC when compared with SCC. Similarly, increased expressions of Matrix Metalloproteinase (MMP), MMP-1, MMP-2 and MMP-9 were reported in BSCC than in SCC, suggesting a more aggressive behavior of BSCC than SCC

18. CONCLUSION BSCC is a distinct clinicopathological entity whose diagnosis still remains on haematoxylin and eosin sections by recognizing the defined histological criteria described two decades ago. However, its aggressive clinical behaviour reiterates prompt diagnosis and treatment. Immunohistochemistry may be a useful diagnostic tool in recognizing such lesions at an early stage.

19. . There is no established consensus for treatment. Surgery of the tumour and the lymph nodes associated with radiotherapy is usually seen in most of the literature. Although considerable controversy still exists regarding the comparative analysis of the clinical course and prognosis of BSCC and conventional SCC. Studies have proven that BSCC is a high-grade variant of conventional SCC, associated with poorer prognosis and increased rate of recurrence. Therefore, rare lesion such as BSCC must be reported for the better understanding of the nature of such tumours.

20. THANK YOU