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Dedifferentiated endometrial adenocarcinoma with neuroendocrine differentiation and ballooning-cell features: Report of a rare entity with an unusual histology
Human Pathology: Case Reports 15 (2019) 92–94
Contents lists available at ScienceDirect
Human Pathology: Case Reports journal homepage: www.elsevier.com/locate/ehpc
Case Report
Dedifferentiated endometrial adenocarcinoma with neuroendocrine differentiation and ballooning-cell features: Report of a rare entity with an unusual histology
T
⁎
Sara Makhdoum (MD)a,b, M. Ruhul Quddus (MD, M. Phil (Path))a, , Michele M. Lomme (MD)a, Katrine Hansen (MD)a, W. Dwayne Lawrence (MD, MSc (Path))a a b
Department of Pathology, Women & Infants Hospital/Alpert Medical School of Brown University, Providence, RI 02905, USA King Faisal Specialist Hospital and Research Center, Department of Pathology and Laboratory Medicine, Riyadh, Saudi Arabia
A R T I C LE I N FO
A B S T R A C T
Keywords: Endometrium Dedifferentiated carcinoma Neuroendocrine features Balloon-cell change Microsatellite instability
A 63-year-old Caucasian woman underwent total hysterectomy with bilateral salpingo-oophorectomy due to abnormal uterine bleeding. Gross examination of the hysterectomy specimen revealed a large polypoid mass filling the endometrial cavity. Histological examination revealed a tumor with two unique morphologic patterns with no overlap or transition from one pattern to the other. The low-grade component consisted of FIGO grade 1 endometrioid adenocarcinoma with unusual “balloon-cell” change, while the high grade component was an undifferentiated carcinoma with neuroendocrine features. Both components exhibited MLH1 and MSH6 loss by immunohistochemistry. To our knowledge, the current case is only the 5th documented case of dedifferentiated endometrioid carcinoma with neuroendocrine features.
1. Introduction
2. Case report
Dedifferentiated endometrial carcinoma (DEC) is a rare tumor that accounts for less than 2% of all carcinomas of the endometrium [1]. It has a unique histologic appearance in that a low-grade carcinoma coexists with a distinctly separate, high-grade undifferentiated component with no overlap or transition between the two morphologic patterns. The low grade component usually consists of endometrioid adenocarcinoma, either FIGO grade I or II [2]. The high-grade, or undifferentiated component appears as sheets of discohesive, primitive appearing cells. Characteristically, the two components are directly adjacent, but sharply demarcated from each other. Recently, Espinosa et al. reported 4 cases of dedifferentiated endometrial carcinoma where the dedifferentiated component showed neuroendocrine features (DECNE) [3]. Here we report an additional case of dedifferentiated endometrial carcinoma with neuroendocrine features. The current case also shows an unusual morphologic feature of balloon-cell change in the low-grade component. The prognosis for DECNE has not been well studied due to the small number of reported cases. Therefore, it appears prudent to document such cases in order to better understand the biologic behavior of this rare and unique malignant tumor.
A 63-year-old Caucasian woman, without significant previous clinical history, presented with abnormal uterine bleeding. A total hysterectomy, bilateral salpingo-oophorectomy, and staging procedure were performed. Gross examination revealed a large polypoid mass occupying the endometrial cavity and extending into the lower uterine segment. The tumor appeared to invade deep into the underlying myometrium and lower uterine segment. No cervical involvement was noted. The bilateral ovaries and fallopian tubes were unremarkable. Microscopically, the tumor displayed an undifferentiated endometrioid carcinoma (UEC) component made up of sheets of discohesive cells with areas of necrosis, directly adjacent to a well differentiated endometrioid carcinoma. The UEC component did not show any glandular, squamous, or serous/clear cell differentiation (Fig. 1A–B); however, as has been previously described in UEC's, focal areas of rhabdoid differentiation were noted. The high grade (UEC) component comprised the bulk of the tumor, accounting for at least three-quarters of the neoplasm and had morphologic features of a large cell neuroendocrine carcinoma. Directly adjacent, a low-grade (FIGO 1) endometrioid carcinoma accounted for the remainder of the tumor. “Balloon-cell changes” were seen in many of the glands of the low grade
⁎
Corresponding author at: Department of Pathology, Women & Infants Hospital/Alpert Medical School of Brown University, Providence, RI 02905, USA. E-mail address: [email protected] (M.R. Quddus).
https://doi.org/10.1016/j.ehpc.2019.01.002 Received 23 August 2018; Received in revised form 13 November 2018; Accepted 2 January 2019 2214-3300/ © 2019 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/BY-NC-ND/4.0/).
Human Pathology: Case Reports 15 (2019) 92–94
S. Makhdoum et al.
Fig. 1. Dedifferentiated endometrioid carcinoma (HE 20×): A: Well differentiated glands on left and sheet like single cells on right; B: Higher magnification (HE 40×); C: Well differentiated carcinoma focally showing balloon-cell differentiation (HE x 20×); D: Pancytokeratin, AE1/AE3 immunostain showing differential staining in two components, positive staining only in well-differentiated component. (IHC AE1/AE3 x 10×). E: Synaptophysin immunostain shows strong diffuse positivity only in dedifferentiated component (IHC Synaptophysin x 10×).
component must also be documented as being of epithelial origin by immuno-positivity for at least one cytokeratin marker (namely CAM 5.2, EMA or CK AE1/AE3). Although there are reports of high grade endometrioid carcinoma with neuroendocrine differentiation, dedifferentiated endometrial carcinoma with neuroendocrine differentiation (DENEC) has only recently been reported in the literature when Espinosa et al., reported 4 cases [3]. Here we report a 5th case. Pure UEC is a high-grade tumor with a poor prognosis. The overall 5-year survival has been reported to range from 5% to 25% [2,5]. However, it is important to remember that DEC and UEC are not the same tumor. Indeed, the morphology of the high grade component of these two entities may be similar; namely, monotonous medium or large-sized cells lacking intercellular cohesion and arranged in solid sheets with no appreciable morphologic pattern. However, DEC, by definition, must also display a low grade endometrioid carcinoma component. In addition, the immuno-histochemical profile of UEC may show focal, less than 10%, staining for cytokeratin (AE1/AE3), whereas DEC must show immunohistochemical evidence of epithelial origin. Occasionally, rhabdoid cells may be encountered in DEC [4,6], as seen in our case. Undifferentiated carcinoma with neuroendocrine features may show nesting, trabecular or cord-like growth patterns also [7]. Although of no known prognostic significance, an interesting finding in our case is the balloon-cell differentiation in the low-grade carcinoma component, possibly indicating a potential for diverse differentiation within this entity. To our knowledge, this particular morphologic feature has not been reported in the English literature in this tumor. Recently, endometrial carcinoma has been subtyped into four groups based on molecular expression: POLE ultramutated with high mutation rate and hotspot mutation in POLE genes, hypermutated microsatellite unstable with high mutation rate without POLE gene mutation, copy number low microsatellite stable but high mutation in
endometrioid component (Fig. 1C). The boundary between the two components was abrupt with no definitive overlap or transition. Abundant retraction artifact was noted in the tumor and many foci raised the question of vascular space invasion. The larger ectatic lymphatics and venules contained tumor but likely represented artifact due to the poor fixation and friable nature of the carcinoma. Some of the smaller vessels contained tumor cells that were suspicious, but not definitive, for vascular space invasion. Immuno-histochemical stains revealed strong and diffuse positivity for cytokeratin (AE1/AE3) in the low-grade endometrioid component, whereas the high grade undifferentiated component was negative (Fig. 1D). Conversely, the neuroendocrine marker synaptophysin displayed the opposite staining pattern, with the low grade component negative and the undifferentiated component being positive (Fig. 1E). Both components stained with antibodies to CAM 5.2 (Fig. 2A–B), supporting the diagnosis of so-called ‘dedifferentiated carcinoma’. Loss of nuclear staining for MLH 1 and MSH6 was observed in both components of the tumor (Fig. 2C–D), while hypermethylation was present by PCR-based assay. No extra-uterine spread of tumor was noted by histologic examination. The bilateral ovaries, fallopian tubes and pelvic lymph nodes were all negative for tumor.
3. Discussion Dedifferentiated endometrial carcinoma (DEC) has a unique morphologic pattern and can only be diagnosed when an undifferentiated carcinoma presents as a distinctly separate component of an endometrial tumor directly adjacent to a low grade endometrioid carcinoma. There should be no overlap or transition between the two components [4]. The undifferentiated endometrial carcinoma (UEC) 93
Human Pathology: Case Reports 15 (2019) 92–94
S. Makhdoum et al.
Fig. 2. Dedifferentiated endometrial carcinoma: A: CAM 5.2 staining the well differentiated component (CAM 5.2 20×); B: Focal but strong CAM 5.2 staining in dedifferentiated component (CAM 5.2 20×). C: Loss of nuclear staining for MLH 1 by immunostaining (MLH 1 10×) and D: Loss of nuclear staining for MSH6 by immunostaining (MLH6 10×), background inflammatory cells show positive staining.
Conflict of interest
CTNNB1 gene mutation, and copy number high mostly serous but also some endometrioid carcinoma [3,8]. UEC or DEC, have been reported to be associated with Lynch syndrome [1,9], a condition that is inherited in an autosomal dominant manner and caused by mismatched repair (MMR) genes loss, including MLH1, MSH2, MSH6, and/or PMS [9]. Moreover, studies have shown that loss of MMR in approximately 50% of endometrial carcinomas with neuroendocrine differentiation [7]. The four index cases of DECNE reported by Espinosa et al. [3], found MLH1 and PMS2 loss in two cases. Our case showed loss of nuclear staining for MLH 1, in addition to loss of MSH6, which has not been previously reported. Rosa-Rosa et al. studied 10 cases of UACNE for mismatched repair by immunohistochemistry. In that series, 70% (7/10) of cases were hyper methylated tumors when PCR-based studies were done [6].
None declared. References [1] Joseph T. Rabban, Dedifferentiated endometrial carcinoma: an aggressive tumor that may morphologically mimic lower-grade endometrioid adenocarcinoma, AJSP Rev. Rep. 21 (2) (2016) 57–72. [2] R. Zaino, L.H. Ellenson SGC, et al., Tumors of the uterine corpus (chapter 5), Epithelial tumor and precursors, in: R.J. Kurman, M.I. Carcangui, C.S. Herrington, R.H. Young (Eds.), WHO Classification of Tumours of Female Reproductive Organs, 4th edition, IARC, Lyon, 2014, pp. 132–133. [3] De Leo A. Espinosa, E. D'Angelo, J.M. Rosa-Rosa, M. Corominas, A. Gonzalez, et al., Dedifferentiated endometrial carcinomas with neuroendocrine features: a clinicopathologic, immunohistochemical, and molecular genetic study, Hum. Pathol. 72 (2018) 100–106. [4] J. Han, E.Y. Ki, S.E. Rha, S. Hur, A. Lee, Dedifferentiated endometrioid carcinoma of the uterus: report of four cases and review of literature, World J. Surg. Oncol. 15 (1) (2017) 17. [5] Maysa Al-Hussaini, Shaymaa Al-Loh, Undifferentiated endometrial carcinoma a diagnosis frequently overlooked, Arch. Pathol. Lab. Med. 137 (2013) 438–442. [6] J.M. Rosa-Rosa, S. Leskela, E. Cristobal-Lana, A. Santon, M.A. Lopez-Garcia, G. Munoz, et al., Molecular genetic heterogeneity in undifferentiated endometrial carcinomas, Mod. Pathol. 29 (11) (2016) 1390–1398. [7] Cady E. Pocrnich, Preetha Ramalingam, Elizabeth D. Euscher, Anais Malpica, Neuroendocrine Carcinoma of the Endometrium: A Clinicopathologic Study of 25 Cases, Am. J. Surg. Pathol. 40 (5) (2016) 577–586 May 2016. [8] Cancer Genome Atlas Research N, C. Kandoth, N. Schultz, A.D. Cherniack, R. Akbani, Y. Liu, et al., Integrated genomic characterization of endometrial carcinoma, Nature 497 (7447) (2013) 67–73. [9] S.Y. Park, M.H. Park, H.S. Ko, E.J. Cha, J.S. Sohn, U.S. Jung, et al., Dedifferentiated endometrioid adenocarcinoma of the uterus: highly aggressive and poor prognostic tumor, Korean J. Pathol. 48 (4) (2014) 327–330.
4. Conclusion To our knowledge, this is the fifth documented case of a dedifferentiated endometrial adenocarcinoma with neuroendocrine features and the first case to be reported as having an MSH6 mismatch repair protein loss in the English literature. An additional interesting finding in our case is the unusual “balloon-cell” change in the well differentiated component of the tumor. It is important to identify morphologic and immunohistochemical variations within tumor types as this is often the first step to better understanding potential biologic behaviors. Documentation of these rare tumors is important for future studies and better patient care.
94
Contents lists available at ScienceDirect
Human Pathology: Case Reports journal homepage: www.elsevier.com/locate/ehpc
Case Report
Dedifferentiated endometrial adenocarcinoma with neuroendocrine differentiation and ballooning-cell features: Report of a rare entity with an unusual histology
T
⁎
Sara Makhdoum (MD)a,b, M. Ruhul Quddus (MD, M. Phil (Path))a, , Michele M. Lomme (MD)a, Katrine Hansen (MD)a, W. Dwayne Lawrence (MD, MSc (Path))a a b
Department of Pathology, Women & Infants Hospital/Alpert Medical School of Brown University, Providence, RI 02905, USA King Faisal Specialist Hospital and Research Center, Department of Pathology and Laboratory Medicine, Riyadh, Saudi Arabia
A R T I C LE I N FO
A B S T R A C T
Keywords: Endometrium Dedifferentiated carcinoma Neuroendocrine features Balloon-cell change Microsatellite instability
A 63-year-old Caucasian woman underwent total hysterectomy with bilateral salpingo-oophorectomy due to abnormal uterine bleeding. Gross examination of the hysterectomy specimen revealed a large polypoid mass filling the endometrial cavity. Histological examination revealed a tumor with two unique morphologic patterns with no overlap or transition from one pattern to the other. The low-grade component consisted of FIGO grade 1 endometrioid adenocarcinoma with unusual “balloon-cell” change, while the high grade component was an undifferentiated carcinoma with neuroendocrine features. Both components exhibited MLH1 and MSH6 loss by immunohistochemistry. To our knowledge, the current case is only the 5th documented case of dedifferentiated endometrioid carcinoma with neuroendocrine features.
1. Introduction
2. Case report
Dedifferentiated endometrial carcinoma (DEC) is a rare tumor that accounts for less than 2% of all carcinomas of the endometrium [1]. It has a unique histologic appearance in that a low-grade carcinoma coexists with a distinctly separate, high-grade undifferentiated component with no overlap or transition between the two morphologic patterns. The low grade component usually consists of endometrioid adenocarcinoma, either FIGO grade I or II [2]. The high-grade, or undifferentiated component appears as sheets of discohesive, primitive appearing cells. Characteristically, the two components are directly adjacent, but sharply demarcated from each other. Recently, Espinosa et al. reported 4 cases of dedifferentiated endometrial carcinoma where the dedifferentiated component showed neuroendocrine features (DECNE) [3]. Here we report an additional case of dedifferentiated endometrial carcinoma with neuroendocrine features. The current case also shows an unusual morphologic feature of balloon-cell change in the low-grade component. The prognosis for DECNE has not been well studied due to the small number of reported cases. Therefore, it appears prudent to document such cases in order to better understand the biologic behavior of this rare and unique malignant tumor.
A 63-year-old Caucasian woman, without significant previous clinical history, presented with abnormal uterine bleeding. A total hysterectomy, bilateral salpingo-oophorectomy, and staging procedure were performed. Gross examination revealed a large polypoid mass occupying the endometrial cavity and extending into the lower uterine segment. The tumor appeared to invade deep into the underlying myometrium and lower uterine segment. No cervical involvement was noted. The bilateral ovaries and fallopian tubes were unremarkable. Microscopically, the tumor displayed an undifferentiated endometrioid carcinoma (UEC) component made up of sheets of discohesive cells with areas of necrosis, directly adjacent to a well differentiated endometrioid carcinoma. The UEC component did not show any glandular, squamous, or serous/clear cell differentiation (Fig. 1A–B); however, as has been previously described in UEC's, focal areas of rhabdoid differentiation were noted. The high grade (UEC) component comprised the bulk of the tumor, accounting for at least three-quarters of the neoplasm and had morphologic features of a large cell neuroendocrine carcinoma. Directly adjacent, a low-grade (FIGO 1) endometrioid carcinoma accounted for the remainder of the tumor. “Balloon-cell changes” were seen in many of the glands of the low grade
⁎
Corresponding author at: Department of Pathology, Women & Infants Hospital/Alpert Medical School of Brown University, Providence, RI 02905, USA. E-mail address: [email protected] (M.R. Quddus).
https://doi.org/10.1016/j.ehpc.2019.01.002 Received 23 August 2018; Received in revised form 13 November 2018; Accepted 2 January 2019 2214-3300/ © 2019 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/BY-NC-ND/4.0/).
Human Pathology: Case Reports 15 (2019) 92–94
S. Makhdoum et al.
Fig. 1. Dedifferentiated endometrioid carcinoma (HE 20×): A: Well differentiated glands on left and sheet like single cells on right; B: Higher magnification (HE 40×); C: Well differentiated carcinoma focally showing balloon-cell differentiation (HE x 20×); D: Pancytokeratin, AE1/AE3 immunostain showing differential staining in two components, positive staining only in well-differentiated component. (IHC AE1/AE3 x 10×). E: Synaptophysin immunostain shows strong diffuse positivity only in dedifferentiated component (IHC Synaptophysin x 10×).
component must also be documented as being of epithelial origin by immuno-positivity for at least one cytokeratin marker (namely CAM 5.2, EMA or CK AE1/AE3). Although there are reports of high grade endometrioid carcinoma with neuroendocrine differentiation, dedifferentiated endometrial carcinoma with neuroendocrine differentiation (DENEC) has only recently been reported in the literature when Espinosa et al., reported 4 cases [3]. Here we report a 5th case. Pure UEC is a high-grade tumor with a poor prognosis. The overall 5-year survival has been reported to range from 5% to 25% [2,5]. However, it is important to remember that DEC and UEC are not the same tumor. Indeed, the morphology of the high grade component of these two entities may be similar; namely, monotonous medium or large-sized cells lacking intercellular cohesion and arranged in solid sheets with no appreciable morphologic pattern. However, DEC, by definition, must also display a low grade endometrioid carcinoma component. In addition, the immuno-histochemical profile of UEC may show focal, less than 10%, staining for cytokeratin (AE1/AE3), whereas DEC must show immunohistochemical evidence of epithelial origin. Occasionally, rhabdoid cells may be encountered in DEC [4,6], as seen in our case. Undifferentiated carcinoma with neuroendocrine features may show nesting, trabecular or cord-like growth patterns also [7]. Although of no known prognostic significance, an interesting finding in our case is the balloon-cell differentiation in the low-grade carcinoma component, possibly indicating a potential for diverse differentiation within this entity. To our knowledge, this particular morphologic feature has not been reported in the English literature in this tumor. Recently, endometrial carcinoma has been subtyped into four groups based on molecular expression: POLE ultramutated with high mutation rate and hotspot mutation in POLE genes, hypermutated microsatellite unstable with high mutation rate without POLE gene mutation, copy number low microsatellite stable but high mutation in
endometrioid component (Fig. 1C). The boundary between the two components was abrupt with no definitive overlap or transition. Abundant retraction artifact was noted in the tumor and many foci raised the question of vascular space invasion. The larger ectatic lymphatics and venules contained tumor but likely represented artifact due to the poor fixation and friable nature of the carcinoma. Some of the smaller vessels contained tumor cells that were suspicious, but not definitive, for vascular space invasion. Immuno-histochemical stains revealed strong and diffuse positivity for cytokeratin (AE1/AE3) in the low-grade endometrioid component, whereas the high grade undifferentiated component was negative (Fig. 1D). Conversely, the neuroendocrine marker synaptophysin displayed the opposite staining pattern, with the low grade component negative and the undifferentiated component being positive (Fig. 1E). Both components stained with antibodies to CAM 5.2 (Fig. 2A–B), supporting the diagnosis of so-called ‘dedifferentiated carcinoma’. Loss of nuclear staining for MLH 1 and MSH6 was observed in both components of the tumor (Fig. 2C–D), while hypermethylation was present by PCR-based assay. No extra-uterine spread of tumor was noted by histologic examination. The bilateral ovaries, fallopian tubes and pelvic lymph nodes were all negative for tumor.
3. Discussion Dedifferentiated endometrial carcinoma (DEC) has a unique morphologic pattern and can only be diagnosed when an undifferentiated carcinoma presents as a distinctly separate component of an endometrial tumor directly adjacent to a low grade endometrioid carcinoma. There should be no overlap or transition between the two components [4]. The undifferentiated endometrial carcinoma (UEC) 93
Human Pathology: Case Reports 15 (2019) 92–94
S. Makhdoum et al.
Fig. 2. Dedifferentiated endometrial carcinoma: A: CAM 5.2 staining the well differentiated component (CAM 5.2 20×); B: Focal but strong CAM 5.2 staining in dedifferentiated component (CAM 5.2 20×). C: Loss of nuclear staining for MLH 1 by immunostaining (MLH 1 10×) and D: Loss of nuclear staining for MSH6 by immunostaining (MLH6 10×), background inflammatory cells show positive staining.
Conflict of interest
CTNNB1 gene mutation, and copy number high mostly serous but also some endometrioid carcinoma [3,8]. UEC or DEC, have been reported to be associated with Lynch syndrome [1,9], a condition that is inherited in an autosomal dominant manner and caused by mismatched repair (MMR) genes loss, including MLH1, MSH2, MSH6, and/or PMS [9]. Moreover, studies have shown that loss of MMR in approximately 50% of endometrial carcinomas with neuroendocrine differentiation [7]. The four index cases of DECNE reported by Espinosa et al. [3], found MLH1 and PMS2 loss in two cases. Our case showed loss of nuclear staining for MLH 1, in addition to loss of MSH6, which has not been previously reported. Rosa-Rosa et al. studied 10 cases of UACNE for mismatched repair by immunohistochemistry. In that series, 70% (7/10) of cases were hyper methylated tumors when PCR-based studies were done [6].
None declared. References [1] Joseph T. Rabban, Dedifferentiated endometrial carcinoma: an aggressive tumor that may morphologically mimic lower-grade endometrioid adenocarcinoma, AJSP Rev. Rep. 21 (2) (2016) 57–72. [2] R. Zaino, L.H. Ellenson SGC, et al., Tumors of the uterine corpus (chapter 5), Epithelial tumor and precursors, in: R.J. Kurman, M.I. Carcangui, C.S. Herrington, R.H. Young (Eds.), WHO Classification of Tumours of Female Reproductive Organs, 4th edition, IARC, Lyon, 2014, pp. 132–133. [3] De Leo A. Espinosa, E. D'Angelo, J.M. Rosa-Rosa, M. Corominas, A. Gonzalez, et al., Dedifferentiated endometrial carcinomas with neuroendocrine features: a clinicopathologic, immunohistochemical, and molecular genetic study, Hum. Pathol. 72 (2018) 100–106. [4] J. Han, E.Y. Ki, S.E. Rha, S. Hur, A. Lee, Dedifferentiated endometrioid carcinoma of the uterus: report of four cases and review of literature, World J. Surg. Oncol. 15 (1) (2017) 17. [5] Maysa Al-Hussaini, Shaymaa Al-Loh, Undifferentiated endometrial carcinoma a diagnosis frequently overlooked, Arch. Pathol. Lab. Med. 137 (2013) 438–442. [6] J.M. Rosa-Rosa, S. Leskela, E. Cristobal-Lana, A. Santon, M.A. Lopez-Garcia, G. Munoz, et al., Molecular genetic heterogeneity in undifferentiated endometrial carcinomas, Mod. Pathol. 29 (11) (2016) 1390–1398. [7] Cady E. Pocrnich, Preetha Ramalingam, Elizabeth D. Euscher, Anais Malpica, Neuroendocrine Carcinoma of the Endometrium: A Clinicopathologic Study of 25 Cases, Am. J. Surg. Pathol. 40 (5) (2016) 577–586 May 2016. [8] Cancer Genome Atlas Research N, C. Kandoth, N. Schultz, A.D. Cherniack, R. Akbani, Y. Liu, et al., Integrated genomic characterization of endometrial carcinoma, Nature 497 (7447) (2013) 67–73. [9] S.Y. Park, M.H. Park, H.S. Ko, E.J. Cha, J.S. Sohn, U.S. Jung, et al., Dedifferentiated endometrioid adenocarcinoma of the uterus: highly aggressive and poor prognostic tumor, Korean J. Pathol. 48 (4) (2014) 327–330.
4. Conclusion To our knowledge, this is the fifth documented case of a dedifferentiated endometrial adenocarcinoma with neuroendocrine features and the first case to be reported as having an MSH6 mismatch repair protein loss in the English literature. An additional interesting finding in our case is the unusual “balloon-cell” change in the well differentiated component of the tumor. It is important to identify morphologic and immunohistochemical variations within tumor types as this is often the first step to better understanding potential biologic behaviors. Documentation of these rare tumors is important for future studies and better patient care.
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