January 2004, Volume 54, Issue 1

Case Reports

Baso-Squamous Cell Carcinoma - a Case Report

S. I. Hussain  ( )
A. S. Hussainy  ( )

Introduction

Basosquamous cell carcinoma (BSCC) is a rare variant of basal cell carcinoma, which carries poor prognosis because of its metastatic potential. We present a case of BSCC of face, treated with radical surgical and adjuvant radiation. This case report stresses the need to critically differentiate BSCC from the close terminology of Basaloid squamous cell carcinoma which is an aggressive variant of squamous cell carcinoma occuring in the upper aerodigestive tract.
Case Report
A 65 year old male reported to Ear, Nose and Throat (ENT) outpatient with painful ulcerative lesion of left lower two third of face. It started as a tiny lesion at left nasomaxillary groove one year back. This gradually increased in size. On clinical examination, it was an ulcerated lesion of 5 cm x 3 cm involving whole upper lip and left angle of mouth but sparing right angle mouth. The lesion extended to involve lower half of collumella and adjacent zygomaxillary region. The margins were irregular and the base was covered with purulent odouriferous secretion with numerous maggots crawling in it. Plain x-ray paranasal sinus (Water's view) did not depict any bony erosion.
Presumptive diagnosis of basal cell carcinoma was made. After cleaning, debridement and parental antibiotics, the whole lesion was excised. On histopathological examination it was diagnosed as Baso-squamous cell carcinoma. The specimen revealed ulcerated surface squamous epithelium. Intact skin adnexae were however present. At low power, the tumor cells were predominantly arranged as cords (Figure 1). There were two types of cells. The peripheral cells were small and arranged in a pallisading pattern. Centrally, the cells showed squamoid differentiation with keratin formation, which were more obvious at high power (Fig ure 2). Brisk mitotic activity was also identified along with inflammatory infiltrate in the stroma. The surgical defect was secondarily covered with horizontal forehead flap. The patient was later sent for adjuvant radiotherapy.

Discussion

Baso-squamous cell carcinoma is a variant of basal cell carcinoma. Basal cell carcinomas are seen almost exclusively on the hair-bearing skin, especially on the face. Except for the nevoid basal cell carcinoma, they rarely occur on the palms1,2 or the soles.3,4 Their occurrence on the mucous membrane is doubted. Basal cell carcinoma of the oral cavity as reported in the literature5, are probably ameloblastomas.6
The existence of basal cell carcinomas with features of squamous cell carcinoma was first postulated in 1922.7 Two types of baso-squamous cell carcinomas (also called metatypical epitheliomas) were recognized: a mixed and an intermediary type. The mixed type was described as showing focal keratinization consisting of pearls with a colloidal or parakeratotic center; and the intermediary type showing within a network of narrow strands two kinds of cells, an outer row of dark-staining basal cells and an inner layer of cells appearing larger, lighter, and better defined than the basal cells (regarded as intermediate in character between basal and squamous cells).
Several authors have accepted the existence of baso-squamous cell carcinoma or metatypical epitheliomas.8,9 They are considered by some to represent a transition from basal cell carcinoma to squamous cell carcinoma. It has been stated a continuum which extends from basal cell carcinoma at one extreme to squamous cell carcinoma at the other end.10 The incidence of baso-squamous cell carcinomas among basal cell carcinomas has been judged to be 3%.10 It has also been stated that baso-squamous cell carcinoma shows a greater tendency to metastasize than basal cell carcinoma.8,9
On the other hand, the existence of BSCC is questioned by many.11 It would seem that the entirely different genesis of squamous cell carcinoma, a true anaplastic carcinoma of epidermis and BCC a tumour composed of immature rather than anaplastic cells, makes the occurence of transitional forms quite unlikely. It can be assumed that the so-called mixed type of BSCC represent a keratotic BCC and the intermediate type represents a BCC with differentiation into two types.
Basaloid squamous carcinoma, on the contrary is a biologically aggressive variant of squamous cell carcinoma. Wain, first described it in 1986 and reported it as an independent malignancy.12,13 To date 100 cases are reported in literature.13,14 The common site of origin being the upper aero digestive tract, vis-à-vis oral cavity, nasal cavity, nasopharynx, base of tongue, hypo-pharynx and supraglottic larynx. Few cases are reported involving cutaneuos areas of head and neck i.e. face, neck, scalp region14-16 while an extremely rare reported site is vulva.17
This tumor has a high proliferative activity, propensity for local destruction and potential for an early regional and distant metastasis, the behaviour that all together differs from basal cell carcinoma.18-20 The differential diagnosis include adenoid cystic carcinoma, small cell undifferentiated carcinoma, neuroendocrine carcinoma,conventional basal cell carcinoma and squamous cell carcinoma.15,19,21,22
The variants of squamous and basal cell carcinoma are rare, and closely mimic conventional squamous cell carcinoma, basal cell carcinoma etc. It is therefore mandatory to critically evaluate this tumor microscopically; as well as to understand the terminology used by the histopathologist correctly, in order to plan correct line of therapy.

References

1. Johnson DE. Basal-cell epithelioma of the palm. Arch Dermatol 1960;82:253.
2. Hyman AB, Barsky AJ. Basal cell epithelioma of the palm. Arch Dermatol 1965; 92:571.
3. Hyman AB, Michaelides P. Basal-cell epithelioma of the sole. Arch Dermatol 1963;87:481.
4. Lewis HM, Stensas CO, Okun MR. Basal cell epithelioma of the sole. Arch Dermatol 1965;91:623.
5. Williamson JJ, Cohney BC, Henderson BM. Basal cell carcinoma of the mandibular gingiva. Arch Dermatol 1967;95:76.
6. Urmacher C, Pearlman S. An auncommon neoplasm of the oral mucosa. Am J Dermatopathol 1983;5:601.
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11. Holmes EJ, Bennigton JL, Haber SL. Citrulline-containing basal cell carcinomas. Cancer 1968;22:663.
12. Akyol MU, Dursun A, Akyol G, et al. Proliferating cell nuclear antigen immunoreactivity and the presence of P53 mutation in Basaloid squamous cell carcinoma of the larynx. Oncology 1998 55:382-3.
13. Kruslin B, Tomasovic C, Cupic H, et al. Basaloid squamous cell carcinoma of the larynx: report of two cases. Croat Med J 1998; 39:450-2.
14. Sanch-Martin I, Alvarez-Montero OL, Felux-Minz J, et al. Basosquamous carcinoma of the floor of the mouth. Acta Otorrhinolaryngol Esp 2000;51:743-7.
15. Gilcrease MZ, Guzman-Paz M. Fine needle aspiration of basaloid squamous carcinoma: a case report with review of differential diagnostic considerations. Diagn Cytopathol 1998;19:210-15.
16. Muller E, Beleites E. The basaloid squamous cell carcinoma of the nasopharynx. Rhinology. 2000;38:208-11.
17. Li H, Heller DS, Sama J, et al. Basaloid squamous cell carcinima of the vagina metastasizing to the lung: a case report. J Reprod Med 2000;45:841-3.
18. Rickert D, Engelke JC, Tietze L, et al. Case report of a basaloid squamous epithelial carcinoma of the oropharynx: clinical and histopathologic markers of an aggressive tumour entity. Laryngo-rhino-otologie. 1999;78:189-93.
19. Strassburger S, Hyckel P, Schumann D, et al. Basaloid squamous epithelial carcinoma (basaloid- squamous carcinoma) of the mouth floor: differential diagnosis and response to neoadjuvant chemotherapy. Mund- Kiefer-Gesichtchir 1997;1:239-43.
20. Maritn RC 2nd, Edward MJ, Cawte TG, et al. Basosquamous carcinma: analysis of prognostic factors influencing recurrence. Cancer 2000;15:1365-9.
21. Zamecnik M, Skalova A, Pelikam Ket al. Basaloid squamous carcinoma with collagen spheroles and crystalloid. Ann Diagn Pathol 2001;5:233-9.
22. Nishimura W, Naomoto Y, Hamaya K, et al. Basaloid squamous cell carcinoma of oesophagus. J Gastroentrol Hepatol 2001;16: 566-90.

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