Background: Basal cell carcinoma (BCC) and trichoepithelioma (TE) have some similarities clinically and histologically. The aim of this work is to evaluate the role of Bcl-2, CD10 and CD34 in differentiation between BCC and TE. Methods: The immunohistochemical expression of Bcl-2, CD10 and CD34 was evaluated in 20 BCCs and 12 TEs in a retrospective study. The localization of these markers in tumor and stromal cells was determined and comparison between BCC and TE was done. Immunohistochemistry for Bcl-2, CD10 and CD34 was performed on sections obtained from formalin-fixed, paraffin-embedded blocks. Bcl-2, CD10 and CD34 immunoreactivity in the stromal and/or tumor cells was determined as follows: negative (0); 1+ (10% - 50% positive cells); and 2+ (>50% positive cells). Results: In BCC (20 cases), the expression of Bcl-2 in stromal cells showed (0) immunoreactivity in 8 cases (40%), (1+) immunoreactivity in 7 cases (35%), and (2+) immunoreactivity in 5 cases (25%). Tumoral cells showed diffuse positivity in 20 out of 20 cases (100%), (1+) immunoreactivity in 5 cases (25%) and (2+) immunoreactivity in 15 cases (75%). On the other hand, the expression of Bcl2 in TE, 4 cases showed positive stromal cells out of 12 (33.33%), (1+) immunoreactivity in 2 cases (16.6%) and (2+) immunoreactivity in 2 cases (16.6%), and 8 cases showed no immunoreactivity. Tumoral cells showed positivity in 12 out of 12 cases (100%), (1+) immunoreactivity in 5 cases (41.6%), (2+) immunoreactivity in 7 cases (58.3%). In BCC cases, the expression of CD10 was noted in stromal cells in 8 out of 20 cases (40%), 5 cases showed positivity in stromal and basaloid cells and 3 cases showed positivity in stromal cells only, and 12 cases showed no immunoreactivity (60%). Tumor cells showed positivity in 11 cases out of 20 (55%), (1+) immunoreactivity in 6 cases (30%), (2+) in 5 cases (25%), and 9 cases showed no immunoreactivity (45%). On the other hand, the expression of CD10 in TE 7 cases showed positive stromal cells out of 12 (58.33%), (1+) immunoreactivity in 5 cases (41.6%) and (2+) in 2 cases (16.6%), and 5 cases showed no immunoreactivity (41.66%). Tumor cells showed positivity in 5 cases out of 12 (41.66%), (1+) immunoreactivity in 4 cases (33.33%) and (2+) in 1 case (8.3%), and 7 cases showed no immunoreactivity (58.33%). In BCC cases, the expression of CD34 was noted in stromal cells in14 cases out of 20 cases (70%), (1+) immunoreactivity in 10 cases (50%) and (2+) in 4 cases (20%), and 6 cases showed no immunoreactivity (30%). On the other hand, the expression of CD34 in TE, 10 cases showed positive stromal cells out of 12 (83.33%), (1+) immunoreactivity in 6 cases (50%) and (2+) in 4 cases (33.33%), and 2 cases showed no immunoreactivity (16.6%). Tumor cells showed no immunoreactivity for CD 34 in both BCC and trichoepithelioma, (100%) negative tumor cells. Significant difference of tumor\stromal cells immunoreactivity for Bcl-2 and CD34 in both BCC and TE but it was insignificant for CD10. Conclusion: We conclude that Bcl-2 CD10, CD34 are useful markers in the differential diagnosis of BCC versus TE.
Basal cell carcinoma (BCC) is the most common cutaneous tumor, accounting for approximately 70% of all malignant diseases of the skin. It is locally aggressive and its metastasis is unusual [
This study involved 32 cases; 20 cases of BCC and 12 cases of trichoepithelioma retrieved from the archives of the histopathology lab of Al Azhar University hospitals. The age, sex and site of lesions were recorded. From each paraffin block, four sections (5 micron each) were prepared for routine hematoxyllin and eosin (H&E), Bcl-2, CD10 and CD34 immunostaining. Sections stained by H&E were examined to detect pattern of growth. Sections that were immunostained for Bcl-2, CD10 and CD34 were examined microscopically to detect positively-stained tumor cells. Positive cells were considered according to (Yada et al., 2004) [
All specimens were examined under a light microscope and the amount of immunupositive tumor cells and stromal cells were evaluated by using a scale of [
The data were collected, tabulated, and statistically analyzed, using Statistical Package for the Social Sciences (SPSS). The Fisher exact and Chi-square tests were employed for comparison between the nominal variables, and the Mann-Whitney U test was used to compare the ordinal variables. A P value less than 0.05 were considered significant for all the tests.
The patients with BCC were comprised of 7 females (35%) and 13 males (65%), ranging in age from 35 - 87 years. All of the BCC cases (20) were localized in the head region, 12 cases of TE 5 males (41.66%) 7 females (58.34%) ranging in age from 33 - 60 years. 11 cases were localized in the face and 1 one in nape area.
The two major components are horn cysts of varying sizes and basaloid epithelial islands, lacking the retraction artifact typical of basal cell carcinoma. The walls of the horn cysts are formed by a few layers of cells. Some of the basophilic islands resemble follicular papillae (
Nodular (8 cases; 40%) characterized by variable-sized nodules of basaloid tumor cells with elongated hyperchromatic nuclei and scant cytoplasm, peripheral palisading and clefts between tumor and surrounding stroma (
Superficial (6 cases; 30%), buds and irregular proliferations of tumor tissue attached to the undersurface of the epidermis, with clefts at the interface with the dermis.
Adenoid cystic (3 cases; 15%), show a cribriform or pseudoglandular architecture (usually with an overall nodular growth pattern) associated with mucinous stroma.
Infiltrative (3 cases; 15%), with more atypia and the infiltrating cords of basaloid cells are slender and widely infiltrative, consistent with the so-called morpheic variant of basal cell carcinoma.
Stromal and tumor cells (peripheral and/or central) expression of Bcl2, CD10 and CD34 was graded from [
A comparison of Bcl-2, CD10 and CD34 expression between the BCC and TE groups is displayed in
. Expression of CD10, Bcl-2 and CD34 in BCC
BCC | Bcl-2 | CD10 | CD34 | |||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Immuno reactivity | Stromal | % | Tumor | % | Stromal | % | Tumor | % | Stromal | % | Tumor | % |
(0) | 8 | 40% | 0 | 0% | 12 | 60% | 9 | 45% | 6 | 30% | 20 | 100% |
(1+) | 7 | 35% | 5 | 25% | 7 | 35% | 6 | 30% | 10 | 50% | 0 | 0% |
(2+) | 5 | 25% | 15 | 75% | 1 | 5% | 5 | 25% | 4 | 20% | 0 | 0% |
Total | 20 | 100% | 20 | 100% | 20 | 100% | 20 | 100% | 20 | 100% | 20 | 100 |
. Expression of CD10, Bcl-2 and CD34 in trichoepithelioma
Trichoepithelioma | Bcl-2 | CD10 | CD34 | |||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Immune reactivity | Stromal | % | Tumor | % | Stromal | % | Tumor | % | Stromal | % | Tumor | % |
(0) | 8 | 66.6% | 0 | 0% | 5 | 41.6% | 7 | 58.3% | 2 | 16.6% | 12 | 100% |
(1+) | 2 | 16.6% | 5 | 41.6% | 5 | 41.6% | 4 | 33.3% | 6 | 50% | 0 | 0% |
(2+) | 2 | 16.6% | 7 | 58.3% | 2 | 16.6% | 1 | 8.3% | 4 | 33.3% | 0 | 0% |
Total | 12 | 100% | 12 | 100% | 12 | 100% | 12 | 100% | 12 | 100% | 12 | 100% |
. Expression of CD10, Bcl-2 and CD34 in BCC
BCC | Bcl-2 | CD10 | CD34 | |||
---|---|---|---|---|---|---|
Intensity | Stromal cell | Tumor cell | Stromal cell | Tumor cell | Stromal cell | Tumor cell |
Positive | 12 | 20 | 8 | 11 | 14 | 0 |
Negative | 8 | 0 | 12 | 9 | 6 | 20 |
Total | 20 | 20 | 20 | 20 | 20 | 20 |
P-value | 0.2517 | <0.0001 | 0.2517 | 0.4119 | 0.0577 | <0.0001 |
*P-value < 0.05 is significant. So, Bcl2 staining is significant in tumor cells and insignificant in stromal cells, CD34 staining is significant in tumor cells and insignificant in stromal cells, and CD10 staining is insignificant in both tumor and stromal cells.
. Expression of CD10, Bcl-2 and CD34 in trichoepithelioma
Trichoepithelioma | Bcl-2 | CD10 | CD34 | |||
---|---|---|---|---|---|---|
Intensity | Stromal cell | Tumor cell | Stromal cell | Tumor cell | Stromal cell | Tumor cell |
Positive | 4 | 12 | 7 | 5 | 10 | 0 |
Negative | 8 | 0 | 5 | 7 | 2 | 12 |
Total | 12 | 12 | 12 | 12 | 12 | 12 |
P-value | 0.1938 | 0.0002 | 0.3872 | 0.3872 | 0.0193 | 0.0002 |
So, Bcl2 staining is significant in tumor cells and insignificant in stromal cells, CD34 staining is significant in tumor cells and stromal cells, and CD10 staining is insignificant in tumor cells and stromal cells.
. Expression of Bcl-2 in BCC vs trichoepithelioma
Bcl-2 | Stromal Cell | Tumor Cell | ||||
---|---|---|---|---|---|---|
Intensity | Positive | Negative | P-value | Positive | Negative | P-value |
BCC | 12 | 8 | 0.2517 | 20 | 0 | <0.0001 |
Trichoepithelioma | 4 | 8 | 0.1938 | 12 | 0 | 0.0002 |
*P-value < 0.05 is significant, so, Bcl2 staining is significant in tumor cells of both BCC and TE, and insignificant in stromal cells of both BCC and TE.
. Expression of CD10 in BCC vs trichoepithelioma
CD10 | Stromal Cell | Tumor Cell | ||||
---|---|---|---|---|---|---|
Intensity | Positive | Negative | P-value | Positive | Negative | P-value |
BCC | 8 | 12 | 0.2517 | 11 | 9 | 0.4119 |
Trichoepithelioma | 7 | 5 | 0.3872 | 5 | 7 | 0.3872 |
CD10 staining is insignificant in both BCC and TE.
We noted that Bcl-2 immunoreactivity in tumor cells was strong in both BCC and TE, but it is stronger in basal layer in TE (
. Expression of CD34 in BCC vs trichoepithelioma
CD34 | Stromal cell | Tumor cell | ||||
---|---|---|---|---|---|---|
Intensity | Positive | Negative | P-value | Positive | Negative | P-value |
B.C.C | 14 | 6 | 0.0577 | 0 | 20 | <0.0001 |
Trichoepithelioma | 10 | 2 | 0.0193 | 0 | 12 | 0.0002 |
CD34 staining is significant in tumor and stromal cells of TE, and significant in tumor cells of BCC.
TE: Aggregates of basaloid cells in dermis with peripheral palisading, no clefts (H&E ×150)
BCC: infiltrating nodules with surrounding cleft artifacts (H&E ×135)
TE: stronger Bcl-2 staining of basaloid tumor cells, (DAB ×235)
BCC: showing diffuse Bcl-2 staining of tumor cells (DAB ×235)
BCC: showing diffuse Bcl-2 staining of tumor cells (DAB ×360)
TE: CD10 positive stromal cells and negative tumor cells (DAB ×135)
BCC: CD10 stronger staining of peripheral cells of nodules (DAB ×235)
TE: strong CD34 staining of stromal cells, and negative tumor cells (DAB ×360)
BCC: CD34 positive stromal cells and BV, and negative tumor cells (DAB ×360)
In the present study, we examined 20 BCC and 12 TE for Bcl-2, CD10 and CD34 expression to see the immunostaining pattern of BCC and TE and if these makers might aid in the differentiation between the two tumors.
The Bcl-2 positivity was seen in 60% and 100% of BCC stromal cells and tumor cells respectively, While there was 33.3% and 100% Bcl-2 expression in TE stromal cells and tumor cells respectively, and the pattern of staining is diffuse in BCC and stronger in basal layer in TE.
These findings are in agreement with some studies which stated that Bcl-2 diffusely stains the tumor nests in BCC while it stains the outermost cell layers in trichoepithelioma (Verhaegh et al., 1997 [
CD10 positivity was seen in 40% and 55% of BCC stromal cells and tumor cells respectively while there was 58.3% and 41.6% CD10 expression in TE stromal cells and tumor cells respectively.
CD10 immunoreactivity in BCC, basaloid cells are strongly positive while in TE CD10 was strongly positive in peritumoral stromal cells with patchy staining of basaloid cells.
These findings are nearly in agreement with Sengul et al., (2010) which showed condensation of CD10-posi- tive stromal cells around basaloid nests, which was statistically significant in differentiating TE from BCC. Conversely, CD10-positive basaloid cells were seen predominantly in BCC. No BCC cases demonstrated stromal expression alone in that study. The expression of CD10 by peritumoral stroma alone favored a diagnosis of TE, whereas staining of basaloid cells supported a diagnosis of BCC.
Wagoner et al., 2007 showed strong CD10 expression in the tumor cells of superficial BCC.
CD34 positivity was seen in 70% of BCC stromal cells, and 83.3% of TE stromal cells, but tumor cells in both tumors showed no immunoreactivity.
The findings in this study, are in agreement with Sengul et al., (2010) which showed stromal expression of CD34 for 25 (83.3%) of 30 cases in benign tumors of cutaneous appendages originating from hair follicle (BTCOHF) and 9 (30%) of 21 (70%) in BCC. While stromal expression of CD34 for BTCOHF was observing just the adjacent to the tumor islands; it was not like that for BCC. There was CD34 expressions in the surrounding stromas of BCCs with the adjacent zones which were not stained with CD34.
Illueca et al., 1998 [
The findings of this study are different from findings of Kirchmann et al., (1994) [
The findings of this study are different from findings of Naeyaert et al., (2001) which compared the CD34 staining patterns of TE with (fibroepithelioma) and nodular BCC. They also did not detect the peritumoral stromal expression of CD34 in those variants of BCC.
In conclusion we can suggest that bcl-2, CD10, and CD34 are useful markers in differentiation between BCC and TE. Positive immunostaining for bcl-2 tends to be diffuse in BCC, whereas it is peripheral in trichoepithelioma. Positive immunostaining for CD10 in stromal cells around basaloid nests favors TE over BCC. In addition, CD34 is found to be more positive in the stroma of trichoepithelioma than BCC and absent in tumor cells of both tumors. These findings may prove to be of diagnostic help in distinguishing borderline cases, and also offer some possible explanations for the biological differences between these neoplasms.