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Neuroendocrine (Merkel cell) carcinoma of the retroperitoneum with no identifiable primary site.

Boghossian V, Owen ID, Nuli B, Xiao PQ - World J Surg Oncol (2007)

Bottom Line: Since Merkel cell precursors have never been identified within lymph nodes, the latter theory seems more befitting.Moreover, metastasis to the retroperitoneal lymph nodes has been reported as relatively common when compared to other sites such as liver, bone, brain and skin.Wide local excision of the primary tumor is the surgical treatment of choice for localized disease.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Surgery, Brooklyn Hospital Center, 121 Dekalb Ave, Brooklyn, New York, NY 11201, USA. vanboghossian@aol.com

ABSTRACT

Background: Neuroendocrine carcinoma is an aggressive neoplasm that mainly affects elderly Caucasians and typically arises in sun-exposed areas of the skin. The disease is rather rare and only a relatively few cases present with no apparent primary lesion.

Case presentation: We report a case of an 81-year-old Caucasian male with neuroendocrine carcinoma, which initially presented as a large retroperitoneal mass. Pathological and immunohistochemical analysis of the transabdominal CT-guided biopsy specimen revealed tissue consistent with neuroendocrine carcinoma. The patient underwent exploratory laparotomy and the mass was successfully excised along with an associated mesenteric lymph node.

Discussion: There are currently two possible explanations for what occurred in our patient. First, the retroperitoneal mass could be a massively enlarged lymph node where precursor cells became neoplastic. This would be consistent with a presumptive diagnosis of primary nodal disease. Alternatively, an initial skin lesion could have spontaneously regressed and the retroperitoneal mass represents a single site of metastasis. Since Merkel cell precursors have never been identified within lymph nodes, the latter theory seems more befitting. Moreover, metastasis to the retroperitoneal lymph nodes has been reported as relatively common when compared to other sites such as liver, bone, brain and skin.

Conclusion: Wide local excision of the primary tumor is the surgical treatment of choice for localized disease. We propose that further studies are needed to elucidate the true efficacy of chemotherapy in conventional as well as unconventional patients with neuroendocrine carcinoma.

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Microscopic examination reveals tumor composed of monotonous round cells showing scant eosinophilic cytoplasmic rim, round and vesicular nuclei with finely granular and dusty chromatin and multiple nucleoli (A, hematoxylin and eosin ×100). Tumor cells are positive for synaptophysin (B, ×100) and CK 20 (C, ×100).
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Figure 4: Microscopic examination reveals tumor composed of monotonous round cells showing scant eosinophilic cytoplasmic rim, round and vesicular nuclei with finely granular and dusty chromatin and multiple nucleoli (A, hematoxylin and eosin ×100). Tumor cells are positive for synaptophysin (B, ×100) and CK 20 (C, ×100).

Mentions: Chest X-ray was unremarkable. Magnetic resonance imaging (MRI) of the pelvis (Figure 2) confirmed CT findings and showed that the mass abutted and compressed the external iliac vessels. Pseudoaneurysm was ruled out. Gallium and positron emission tomography (PET) scans (Figure 3) revealed localized abnormal activity in the right lower quadrant. Octreoscan showed a solitary, abnormal lesion in the lower right quadrant consistent with previous findings. No other lesions, primary or metastatic, were demonstrated in any of these studies. Meticulous physical examination of the skin and lymph nodes also revealed no suspicious lesions. There was no evidence of appendicitis and biopsy was recommended. Exhaustive pathological and immunohistochemical analysis of the transabdominal CT-guided biopsy specimen (Figure 4) revealed that tumor cells were positive for both synaptophysin and CK 20, but negative for TTF-1, CK7, WT-1, HBME-1, CD45, CD20, CD3, PAP, PSA, S100 and HMB-45. With such a staining profile, a definitive diagnosis of neuroendocrine (Merkel cell) carcinoma was made and we chose to forego further analysis.


Neuroendocrine (Merkel cell) carcinoma of the retroperitoneum with no identifiable primary site.

Boghossian V, Owen ID, Nuli B, Xiao PQ - World J Surg Oncol (2007)

Microscopic examination reveals tumor composed of monotonous round cells showing scant eosinophilic cytoplasmic rim, round and vesicular nuclei with finely granular and dusty chromatin and multiple nucleoli (A, hematoxylin and eosin ×100). Tumor cells are positive for synaptophysin (B, ×100) and CK 20 (C, ×100).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2117014&req=5

Figure 4: Microscopic examination reveals tumor composed of monotonous round cells showing scant eosinophilic cytoplasmic rim, round and vesicular nuclei with finely granular and dusty chromatin and multiple nucleoli (A, hematoxylin and eosin ×100). Tumor cells are positive for synaptophysin (B, ×100) and CK 20 (C, ×100).
Mentions: Chest X-ray was unremarkable. Magnetic resonance imaging (MRI) of the pelvis (Figure 2) confirmed CT findings and showed that the mass abutted and compressed the external iliac vessels. Pseudoaneurysm was ruled out. Gallium and positron emission tomography (PET) scans (Figure 3) revealed localized abnormal activity in the right lower quadrant. Octreoscan showed a solitary, abnormal lesion in the lower right quadrant consistent with previous findings. No other lesions, primary or metastatic, were demonstrated in any of these studies. Meticulous physical examination of the skin and lymph nodes also revealed no suspicious lesions. There was no evidence of appendicitis and biopsy was recommended. Exhaustive pathological and immunohistochemical analysis of the transabdominal CT-guided biopsy specimen (Figure 4) revealed that tumor cells were positive for both synaptophysin and CK 20, but negative for TTF-1, CK7, WT-1, HBME-1, CD45, CD20, CD3, PAP, PSA, S100 and HMB-45. With such a staining profile, a definitive diagnosis of neuroendocrine (Merkel cell) carcinoma was made and we chose to forego further analysis.

Bottom Line: Since Merkel cell precursors have never been identified within lymph nodes, the latter theory seems more befitting.Moreover, metastasis to the retroperitoneal lymph nodes has been reported as relatively common when compared to other sites such as liver, bone, brain and skin.Wide local excision of the primary tumor is the surgical treatment of choice for localized disease.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Surgery, Brooklyn Hospital Center, 121 Dekalb Ave, Brooklyn, New York, NY 11201, USA. vanboghossian@aol.com

ABSTRACT

Background: Neuroendocrine carcinoma is an aggressive neoplasm that mainly affects elderly Caucasians and typically arises in sun-exposed areas of the skin. The disease is rather rare and only a relatively few cases present with no apparent primary lesion.

Case presentation: We report a case of an 81-year-old Caucasian male with neuroendocrine carcinoma, which initially presented as a large retroperitoneal mass. Pathological and immunohistochemical analysis of the transabdominal CT-guided biopsy specimen revealed tissue consistent with neuroendocrine carcinoma. The patient underwent exploratory laparotomy and the mass was successfully excised along with an associated mesenteric lymph node.

Discussion: There are currently two possible explanations for what occurred in our patient. First, the retroperitoneal mass could be a massively enlarged lymph node where precursor cells became neoplastic. This would be consistent with a presumptive diagnosis of primary nodal disease. Alternatively, an initial skin lesion could have spontaneously regressed and the retroperitoneal mass represents a single site of metastasis. Since Merkel cell precursors have never been identified within lymph nodes, the latter theory seems more befitting. Moreover, metastasis to the retroperitoneal lymph nodes has been reported as relatively common when compared to other sites such as liver, bone, brain and skin.

Conclusion: Wide local excision of the primary tumor is the surgical treatment of choice for localized disease. We propose that further studies are needed to elucidate the true efficacy of chemotherapy in conventional as well as unconventional patients with neuroendocrine carcinoma.

Show MeSH
Related in: MedlinePlus