Wilms종양의 병리조직학적 및 면역조직화학적 특성

Abstract

[한글]

Wilms 종양은 유소아기에 흔한 원발성 악성종양의 하나로 후신발생모체(metanephrogenic blastema)의 미분화 세포에서 기원한다고 알려져 있다. 과거에는 치사율이 높은 종양이

었으나 수술, 항암화학요법 및 방사선 치료의 병합요법으로 2년 생존율이 80% 이상으로 향상되어 치료가능한 악성종양의 하나로 알려져 있다. 그러나 실재로 Wilms 종양과 병리조직학적으로 감별이 대단히 어려운 다른 신장 종양이 있을 뿐 아니라 Wilms 종양의 범주

내에서도 조직학적 소견에 따라 생물학적 경과에 차이가 있다는 보고도 있다. 이에 저자는 Wilms 종양으로 진단된 32예에 대하여 면밀한 광학현미경적 검색으로 조직학적 유형의 분류와 더불어 역분화의 유무를 결정하고 면역조직화학적 검색을 시행하여 다음과 같은 결과를 얻었다.

1. 진단 당시의 환자의 연령 분포는 대부분이 5세 이하로 75.0%였고 그중 2세 이하는 40.7% 였다. 66세에 진단된 성인형 1예가 포함되었다.

2. 조직학적 유형은 혼합형이 62.5%로 가장 많았고, 그 다음으로 상피 우세형, 배질우세형, 간질 우세형의 순으로 나타났다.

3. 역분화는 3예(9.4%)애서 관찰되었는데, 2예는 상피 우세형에 1예는 배질 우세형에 속하였다.

4. 치료 방법과 역분화 존재의 유무는 환자의 5년 생존율과 유의한 상관관계를 보였고, 2세 이하에 진단되거나 또는 남아의 경우에 5년 생존율이 다소 높게 나타났으나 통계학적 유의성은 없었다.

5. 면역조직화학 염색상 Wilms 종양의 상피 성분은 모두 cytokeratin에 양성이었다.

6. Wilms 종양의 배질은 56.3%가 cytokeratin과 vimentin에 모두 양성이었고, 34.4%는 모두 음성이었으며, cytokeratin이 5% 이상의 세포에서 양성인 예는 20예(62.5%)로 배질을 확인하는데 cytokeratin이 vimentin보다 유용하였다.

7. Wilms 종양의 간질 성분은 대부분(81.3%)이 특수 조직으로의 분화를 보이지 않았으며 이들은 면역조직화학 염색상 부분적으로 근섬유모세포성 분화를 보이는 것으로 나타났고, 6예(18.7%)의 횡문근모세포성 분화를 보인 예중 4예가 desmin에 양성이었다.

8. Cytokeratin에 대한 면역조직화학 염색 소견은 Wilms 종양과는 생물학적 경과나 치료방법에 차이가 있는 투명세포 육종, 악성 횡문근양 종양, 중배엽성 신종과의 감별 진단에 도움이 되었다.

이상의 결과로 본 연구에서는 역분화의 존재 유무와 적극적 병합치료 요법의 시행 여부는 예후에 영향을 미치는 중요인자로 나타났고, Wilms 종양에 특징적인 배질을 확인하는데 cytokeratin이 vimentin보다 유용하였으며, 이는 다른 신장 종양과의 감별에도 도움이 되는 것으로 사료된다.

Histopathological and immunohistochemical features Of Wilms' tumor

Yoon Jung Choi

Department of Dental Science, The Graduate School, Yonsei University

(Directed by Assistant Professor Woo Hee Jung)

Wilms' tumor is one of the most common primary malignant tumors of the kidney

during infancy and childhood and is known to be originated from the primitive cells

of metanephric blastema. It presents difficulties when encountered in deciding the

presence of anaplasia or in differentiating it from other renal tumors of childhood

with different biologic behavior because of its diverse histologic patterns and

varying degree of differentiation. Evaluation of clinical and histopathologic

features in terms of prognostication was done on 32 cases of Wilms' tumor which

were surgically resected and diagnosed in the period from January 1979 through June

1992. Immunohistochemical reaction for cytokeratin, vimentin, actin and desmin was

also analysed on all cases of Wilms' tumor in conjunction with clear cell sarcoma

of the kidney(CCSK),malignant rhabdoid tumor of the kidney (MRTK) and congenital

mesoblastic nephroma(CMN) to assess the validity of immunohistochemistry in

differentiating Wilms' tumor from these renal tumours. Histologic classification

and clinical staging of the tumor based on the National Wilms' Tumor Study(NWTS)

was app1ied.

The results were as follows.

1. Twenty four(75%) cases were diagnosed before the age of 5 and 40.7% were under

2 years old.

2. Mixed type was most common(62.5%), followed by epithelial, blastemal and

stromal predominant type in descending order of frequency.

3. Anaplasia was observed in 3 cases(9.4%), two of which were epithelial

predominant type and one blastemal predominant type.

4. Treatment modality and presence of anaplasia were significantly correlated

with 5 year survival rate of patients.

5. Immunohistochemical stain revealed that all epithelial component of Wilms'

tumor were positive for cytokeratin and 56.3% of Wilms' tumor had blastemal

component which were positive for both cytokeratin and vimentin. Twenty

cases(62.5%) of Wilms' tumor had blastemal component which were positive for

cytokeratin with a proportion of more than 5% of reactive cells.

6. Stromal component of Wilms' tumor generally did not show differentiation into

the specialized type of tissue and all revealed positive reactions for vimentin

among which some revealed positive reactions for action. Only 3 out of 6 cases with

rhabdomyoblastic differentiation were positive for desmin.

7. CCSK, MRTK and CMN which have different biologic behavior and treatment

modality compared to Wilms' tumor showed positivity only for vimentin and/or actin.

In summary, treatment modality and presence of anaplasia are significantly

correlated with patients' survival and the immunohistochemical stain for

cytukeratin is very helpful in confirming the presence of blastemal component and

useful in the differential diagnosis of Wi1ms' tumor from other kinds of pediatric

renal tumors.

[영문]

Wilms' tumor is one of the most common primary malignant tumors of the kidney during infancy and childhood and is known to be originated from the primitive cells of metanephric blastema. It presents difficulties when encountered in deciding the presence of anaplasia or in differentiating it from other renal tumors of childhood with different biologic behavior because of its diverse histologic patterns and varying degree of differentiation. Evaluation of clinical and histopathologic features in terms of prognostication was done on 32 cases of Wilms' tumor which

were surgically resected and diagnosed in the period from January 1979 through June 1992. Immunohistochemical reaction for cytokeratin, vimentin, actin and desmin was also analysed on all cases of Wilms' tumor in conjunction with clear cell sarcoma

of the kidney(CCSK),malignant rhabdoid tumor of the kidney (MRTK) and congenital mesoblastic nephroma(CMN) to assess the validity of immunohistochemistry in differentiating Wilms' tumor from these renal tumours. Histologic classification and clinical staging of the tumor based on the National Wilms' Tumor Study(NWTS) was app1ied.

The results were as follows.

1. Twenty four(75%) cases were diagnosed before the age of 5 and 40.7% were under 2 years old.

2. Mixed type was most common(62.5%), followed by epithelial, blastemal and stromal predominant type in descending order of frequency.

3. Anaplasia was observed in 3 cases(9.4%), two of which were epithelial predominant type and one blastemal predominant type.

4. Treatment modality and presence of anaplasia were significantly correlated with 5 year survival rate of patients.

5. Immunohistochemical stain revealed that all epithelial component of Wilms' tumor were positive for cytokeratin and 56.3% of Wilms' tumor had blastemal component which were positive for both cytokeratin and vimentin. Twenty cases(62.5%) of Wilms' tumor had blastemal component which were positive for cytokeratin with a proportion of more than 5% of reactive cells.

6. Stromal component of Wilms' tumor generally did not show differentiation into the specialized type of tissue and all revealed positive reactions for vimentin among which some revealed positive reactions for action. Only 3 out of 6 cases with rhabdomyoblastic differentiation were positive for desmin.

7. CCSK, MRTK and CMN which have different biologic behavior and treatment modality compared to Wilms' tumor showed positivity only for vimentin and/or actin.

In summary, treatment modality and presence of anaplasia are significantly correlated with patients' survival and the immunohistochemical stain for cytukeratin is very helpful in confirming the presence of blastemal component and useful in the differential diagnosis of Wi1ms' tumor from other kinds of pediatric renal tumors.