Question 26#

Which of these immunohistochemistry markers is incorrectly matched with its skin pathology?

A. Cytokeratin and SCC

HMB45 and BCC. This is incorrect. Melan A, S100 and HMB45 are all markers for melanoma, while BCC markers are less specific and include EMA, CEA and bcl-2. The other markers are correctly attributed.

Question 27#

Melanomas arise from:

A. Superficial keratinocytes

Neural crest cells. 

Question 28#

The following is false concerning basal cell carcinomas:

A. Nodular lesions grow downward deep into the dermis as cords and islands of variably basophilic cells with hyperchromatic nuclei, embedded in a mucinous matrix and are often surrounded by fibroblasts and lymphocytes

Radiotherapy is effective in the treatment of primary BCC, surgically recurrent BCC, radio-recurrent BCC and as adjuvant therapy, and is thought to be the treatment of choice for high-risk disease in patients who are unwilling or unable to tolerate surgery. E is false. Nodular BCCs grow downward deep into the dermis as cords and islands of variably basophilic cells with hyperchromatic nuclei, embedded in a mucinous matrix and are often surrounded by fibroblasts and lymphocytes. Multifocal superficial BCCs originate in the epidermis and often extend over several square centimetres or more. Histological features of aggression include perivascular and perineural invasion 1. In an audit of 1392 BCCs arising in 1165 patients, excised under the care of one surgeon in the 10 years from 1988 to 1997, 99 (7%) were reported histologically as incompletely excised 2. In a study in 2003, surgeons of differing experience (n=19) marked excision margins of 2, 5 and 10mm around a standard circular lesion drawn on paper 3. Use of surgical markers, rulers and loupe magnification were all permitted, with five attempts for each margin. The percentage error found was 35, 14 and 4% for the 2, 5 and 10mm margins, respectively (regardless of the grade of surgeon). Repetition of the experiment on volunteer skin demonstrated a percentage error of 45, 16 and 8% for 2, 5 and 10mm margins (significantly greater than the corresponding errors on paper, p<0.001 in all cases). Radiotherapy is NOT effective in the treatment of radio-recurrent BCC. 

References:

1. Telfer NR, Colver GB, Morton CA; British Association of Dermatologists. Guidelines for the management of basal cell carcinoma. Br J Dermatol 2008; 1 59(1): 35-48.
2. Griffiths RW. Audit of histologically incompletely excised basal cell carcinomas: recommendations for management by re-excision. Br J Plast Surg 1999; 52(1): 24-8.
3. Lalla R, Brown TL, Griffiths RW. Where to draw the line: the error in marking surgical excision margins defined. Br J Plast Surg 2003; 56(6): 603-6.
4. Kumar V, Abbas AK, Fausto N. Robbins & Cotran pathologic basis of disease, 7th ed. Philadelphia, USA: WB Saunders, 2004

Question 29#

Which of the following are predisposing risk factors for the development of skin cancer?

A. Sebaceous naevus of Jadassohn

All of the above. Sebaceous naevus of Jadassohn (organoid naevus) has a propensity to BCC development (amongst other benign and malignant tumours). Gorlin’s syndrome (basal cell naevus syndrome) is also associated with BCCs. Albinism is associated with an increased risk of both SCC and BCC. Xeroderma pigmentosa is associated with a significantly increased risk of BCC, SCC and melanoma.

Question 30#

The following best describes a 1.1mm ulcerated melanoma with micrometastasis in a sentinel lymph node:

A. T2bN1b

Stage 3B. The AJCC classification for melanoma is widely published.

References:
1. Balch CM, Buzaid AC, Soong SJ, Atkins MB, Cascinelli N, Coit DG, Fleming ID, Gershenwald JE, Houghton A Jr, Kirkwood JM, McMasters KM, Mihm MF, Morton DL, Reintgen DS, Ross MI, Sober A, Thompson JA, Thompson JF. Final version of the American Joint Committee on Cancer Staging system for cutaneous melanoma. J Clin Oncol 2001; 19(16): 3635-48.