AJR 2004; 182:1194
© American Roentgen Ray Society
Radiologic-Pathologic Conferences of The University of Texas
M. D. Anderson Cancer Center |
Myeloid Sarcoma of the Appendix Mimicking Acute Appendicitis
Sanjay Khatti1,
Silvana C. Faria1,
L. Jeffrey Medeiros2 and
Janio Szklaruk1
1 Department of Diagnostic Imaging, The University of Texas M. D. Anderson
Cancer Center, 1515 Holcombe Blvd., Box 57, Houston, TX 77030.
2 Department of Hematopathology, The University of Texas M. D. Anderson Cancer,
Houston, TX 77030.
Received September 4, 2003;
accepted after revision September 25, 2003.
Address correspondence to J. Szklaruk
(jszklaru{at}di.mdacc.tmc.edu).
A29-year-old man presented with right lower quadrant abdominal pain that he
had been experiencing for 1 day. His medical history was significant for acute
myeloid leukemia. The clinical presentation was of suspected acute
appendicitis. The results of the routine laboratory tests were within normal
limits with the exception of a slight increase in the WBC to 10.4 x
109/L over 3 days. CT showed an enlarged thick-walled abnormal
appendix and inflammatory changes in the right lower quadrant
(Fig. 1A) consistent with acute
appendicitis. At surgery, the appendix was found to be extremely edematous and
inflamed. Gross pathologic evaluation showed an appendix that was 8.0 cm long
and 0.9 cm in greatest diameter with an edematous serosa. Histologic sections
of the appendix showed a neoplasm surrounding the appendix, involving the
periappendicular adipose tissue and serosa, and partially invading the muscle
wall (Fig. 1B). The neoplastic
cells were medium-sized with blastic chromatin, irregular nuclear contours,
and prominent nucleoli (Fig.
1C). The final pathologic diagnosis was myeloid sarcoma. Myeloid
sarcoma is a rare solid tumor of myelogenous cells occurring in an
extramedullary site [1]. This
tumor is also known as chloroma, extramedullary cell tumor, granulocytic
sarcoma, and most recently as myeloid sarcoma
[1–3].
Myeloid sarcoma is most frequently found in patients with both acute and
chronic myelogenous leukemia. However, it also can be found in association
with other myeloproliferative disorders including myeloid metaplasia,
myelofibrosis, polycythemia vera, and chronic eosinophilic leukemia. Myeloid
sarcoma can also precede acute myelogenous leukemia. The rate of occurrence is
approximately 3–9% of patients with acute myelogenous leukemia. Myeloid
sarcoma is found more than twice as often in children as in adults. No
significant sex predominance is apparent
[1,
3].
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Fig. 1A. —29-year-old man with myeloid sarcoma mimicking acute
appendicitis. Contrast-enhanced axial CT scan of pelvis reveals mildly
distended, fluid-filled, thick-walled abnormal appendix (black arrow)
and edema (white arrow) in surrounding fat.
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Fig. 1B. —29-year-old man with myeloid sarcoma mimicking acute
appendicitis. Histopathologic section shows myeloid sarcoma partially
surrounding appendix (asterisk) and invading appendiceal muscle wall
(arrow). (H and E, x20)
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These tumors can involve any part of the body, but the most common sites of
occurrence are orbits and subcutaneous soft tissues. Other locations that have
been described include paranasal sinuses, lymph nodes, bone, spine, brain,
pleural and peritoneal cavities, breasts, thyroid gland, salivary glands,
small bowel, lungs, and testes
[1–3].
Myeloid sarcomas occurring without blood and bone marrow involvement usually
respond to local radiation therapy
[2].
Myeloid sarcoma generally presents as soft-tissue–density discrete
solid nodules or masses. On unenhanced CT images, the soft-tissue myeloid
sarcoma masses are usually isodense compared with muscle. MRI shows isointense
and mildly hyperintense tumors relative to muscle on T1- and T2-weighted
images, respectively [1,
2]. Variable homogeneous
enhancement may be seen after injection of contrast material
[2].
To our knowledge, myeloid sarcoma of the appendix mimicking acute
appendicitis has never been described in the literature. Other pathologic
conditions, however, have been reported to mimic appendicitis, including
Burkitt's lymphoma of the appendix, ulcerative colitis, and eosinophilic
gastroenteritis [4].
A specific CT diagnostic of acute appendicitis can be made when the
abnormal appendix is identified or when a pericecal abscess or phlegmon is
seen in association with an appendicolith
[5]. In our patient, the
radiologic appearance of an enlarged thick-walled appendix with inflammatory
changes in the surrounding fat was characteristic of acute appendicitis. The
surgical and gross pathology findings of an edematous and inflamed appendix
and an edematous serosa correlated with the radiologic picture. In this
patient with a medical history of acute myelogenous leukemia, the final
histologic diagnosis was of myeloid sarcoma, the clinicopathologic and
radiologic presentation of which mimicked acute appendicitis.
References
- Pui MH, Fletcher BD, Langston JW. Granulocytic sarcoma in childhood
leukemia: imaging features. Radiology1994; 190:698
–702[Abstract/Free Full Text]
- Ooi GC, Chim CS, Khong PL, et al. Radiologic manifestations of
granulocytic sarcoma in adult leukemia. AJR2001; 176:1427
–1431[Abstract/Free Full Text]
- Guermazi A, Feger C, Rousselot P, et al. Granulocytic sarcoma
(chloroma): imaging findings in adults and children.
AJR 2002;178:319
–325[Free Full Text]
- Tran D, Salloum L, Tshibaka C, Moser R. Eosinophilic
gastroenteritis mimicking acute appendicitis. Am Surg2000; 66:990
–992[Medline]
- Balthazar EJ, Gordon RB. CT of appendicitis. Semin
Ultrasound CT MR 1989;104:326
–40
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