A 73-year-old man presented with abdominal pain 4 months after allogeneic hematopoietic cell transplantation for complex karyotype acute myeloid leukemia (AML). Endoscopy revealed a polypoid mass lesion in the gastric body. Neoplastic cells distorted mucosa and submucosa (hematoxylin and eosin) (panels A-B) and were immunoreactive for simple epithelial cytokeratin (CK) 8 and for CK antibodies AE1/AE3 (panel C), suggestive of a small cell neuroendocrine carcinoma. In the absence of neuroendocrine markers, a strong positivity for CD34 (panel D) and a coexpression of CK 18 (panel E, brown) with CD33 (panel E, red) in identical cells (panel E) could be demonstrated consistent with a CK+ myeloid sarcoma. Simultaneous bone marrow (BM) aspirate smear (panel F) and biopsy contained blasts positive for CK (panels G-H; brown) in coexpression with CD33 (panel H, red). Retrospectively, an identical CK+ blast phenotype was detected in the BM at initial diagnosis. Original magnifications: panel A, ×5; panels B-C, ×40; panels D,F, ×63; panels E,G-H, ×100.
It seems important to note that CK filaments that are considered as a hallmark of epithelial differentiation may aberrantly be expressed not only in malignant lymphomas, but exceptionally in BM and extramedullary AML infiltrates, as described in the skin [Pathology. 2000;32(2):98-101].
A 73-year-old man presented with abdominal pain 4 months after allogeneic hematopoietic cell transplantation for complex karyotype acute myeloid leukemia (AML). Endoscopy revealed a polypoid mass lesion in the gastric body. Neoplastic cells distorted mucosa and submucosa (hematoxylin and eosin) (panels A-B) and were immunoreactive for simple epithelial cytokeratin (CK) 8 and for CK antibodies AE1/AE3 (panel C), suggestive of a small cell neuroendocrine carcinoma. In the absence of neuroendocrine markers, a strong positivity for CD34 (panel D) and a coexpression of CK 18 (panel E, brown) with CD33 (panel E, red) in identical cells (panel E) could be demonstrated consistent with a CK+ myeloid sarcoma. Simultaneous bone marrow (BM) aspirate smear (panel F) and biopsy contained blasts positive for CK (panels G-H; brown) in coexpression with CD33 (panel H, red). Retrospectively, an identical CK+ blast phenotype was detected in the BM at initial diagnosis. Original magnifications: panel A, ×5; panels B-C, ×40; panels D,F, ×63; panels E,G-H, ×100.
It seems important to note that CK filaments that are considered as a hallmark of epithelial differentiation may aberrantly be expressed not only in malignant lymphomas, but exceptionally in BM and extramedullary AML infiltrates, as described in the skin [Pathology. 2000;32(2):98-101].
For additional images, visit the ASH IMAGE BANK, a reference and teaching tool that is continually updated with new atlas and case study images. For more information visit http://imagebank.hematology.org.
![A 73-year-old man presented with abdominal pain 4 months after allogeneic hematopoietic cell transplantation for complex karyotype acute myeloid leukemia (AML). Endoscopy revealed a polypoid mass lesion in the gastric body. Neoplastic cells distorted mucosa and submucosa (hematoxylin and eosin) (panels A-B) and were immunoreactive for simple epithelial cytokeratin (CK) 8 and for CK antibodies AE1/AE3 (panel C), suggestive of a small cell neuroendocrine carcinoma. In the absence of neuroendocrine markers, a strong positivity for CD34 (panel D) and a coexpression of CK 18 (panel E, brown) with CD33 (panel E, red) in identical cells (panel E) could be demonstrated consistent with a CK+ myeloid sarcoma. Simultaneous bone marrow (BM) aspirate smear (panel F) and biopsy contained blasts positive for CK (panels G-H; brown) in coexpression with CD33 (panel H, red). Retrospectively, an identical CK+ blast phenotype was detected in the BM at initial diagnosis. Original magnifications: panel A, ×5; panels B-C, ×40; panels D,F, ×63; panels E,G-H, ×100. / It seems important to note that CK filaments that are considered as a hallmark of epithelial differentiation may aberrantly be expressed not only in malignant lymphomas, but exceptionally in BM and extramedullary AML infiltrates, as described in the skin [Pathology. 2000;32(2):98-101].](https://ash.silverchair-cdn.com/ash/content_public/journal/blood/128/3/10.1182_blood-2016-04-712109/4/m_460f1.jpeg?Expires=1764997315&Signature=viyRkEpHgar9PGGhw5X9QpPWGLXaZ0Tlusp7zPv-Mz6KT0SghxKedRb9wkdQoePUgJhO3wPcVOr8OM0ISlqrvg6~bF4e0MIHzA1ebGC6kgKVNuvXQXpCTvksZVgO9Pnj0FryBw6JqDJhdt3DUQw8iXiPzy5wDkTuJA07l7QN2XzeGiPy2IMzAyc36NGlas1LsOh1yhsWYMxgXDuDOLVTiQmsD6ovpykVVme9gMo~2tNFPCVMmQVsE1oIxjzd2zddwKaiH5ZABFZaXQnI~0LEu0etaf7FecYwMVhfmnxaJbnjyJgjkycWQcVAuf6H1Mqv-cWqQ3AsdHjpE-nhricbLw__&Key-Pair-Id=APKAIE5G5CRDK6RD3PGA)
This feature is available to Subscribers Only
Sign In or Create an Account Close Modal