Myeloid Sarcoma is a rare tumor composed of myeloblasts occurring at an extramedullary site like bones, or various soft tissues. Myeloid sarcoma may involve the gastrointestinal tract very rarely either solitarily, or occurring simultaneously with acute myeloid leukemia. Its diagnosis is challenging and needs biopsy and immunohistochemical staining. We are describing a case of myeloid sarcoma which presented as a painful anal ulcer mimicking an atypical fissure. Its appearance resembled crohn’s disease on sigmoidoscopy. A biopsy of the ulcer along with histochemical staining led to the diagnosis of myeloid sarcoma. Our case demonstrates the need for aggressive evaluation of any common gastrointestinal complaint with an atypical presentation.
Myeloid Sarcoma, also know as, “Chloroma,” “Granulocytic Sarcoma,” “Myeloblastoma,” or “extramedullary myeloid tumor,” is a tumor formed by immature myeloid cells or myeloblasts at an extramedullary site. Myeloid Sarcoma can precede the onset of acute myeloid leukemia and can also occur during active phase of leukemia. It may indicate the relapse of leukemia in a previously treated patient, or the blastic transformation of a chronic myeloid leukemia. Head and neck structures, bones, oral cavity, soft tissues, lymph nodes, skin, mediastinum, and reproductive organs are frequent sites of involvement of myeloid sarcoma. The involvement of the gastrointestinal tract is very rare. We report a unique case of myeloid sarcoma presenting as a large painful anorectal ulcer mimicking an anal fissure and Crohn’s disease in a young pregnant woman.
A 30-year-old pregnant Caucasian female complaining of severe anal pain and an anal bump was referred to the Colorectal Surgery Office by her primary care physician. She was 8-week pregnant. Her pain started a few days earlier and she noticed a small amount of bright red blood on the toilet paper and coating the stools. She had been constipated. She stated the pain was worse during and after defecation. Her medical history was significant for irritable bowel syndrome, recurrent oral ulcers, and anal pruritis. She denied abdominal pain, nausea, or vomiting. Her family history was significant for inflammatory bowel disease in her maternal relatives. She denied any history of anal intercourse or instrumentation.
Upon examination there were no significant physical findings with the exception of what appeared to be an atypical fissure with heaped up skin edges and ulceration in the center in the left posterior position. A local block was placed and a steroid injection was performed. Topical lidocaine mixed with diltiazem and high fiber supplementation were prescribed.
Her pain transiently improved but upon repeat examination two weeks later she was having recurrent pain and there was no change in the appearance of the fissure. She was admitted for pain control, an examination under anesthesia, and a flexible sigmoidoscopy. The differential diagnosis upon admission was new onset Crohn’s Disease or a severe anal fissure. Upon admission, her vitals were normal and anal inspection revealed two large skin tags. A digital rectal exam could not be done secondary to severe tenderness. Labs showed normal serum electrolytes, WBC 3900, platelets 133000, Hb 11 g/dL, Hct 31.5, and MCV 91.
She was taken to the operating room and examination demonstrated a large deep anal canal ulcer in the left posterior-lateral position (Figure
Large ano-rectal ulcer on exam under anesthesia.
In the following few days, the results of the peripheral blood smear and pathology returned. The smear contained 5% blasts. The biopsy from the anal ulcer depicted squamous mucosa with ulceration and submucosal atypical hematopoietic cell infiltrates suggestive of acute leukemia. Similar findings of discrete mucosal and submucosal aggregates of atypical large and medium-sized hematopoietic cells were noted on rectal biopsies. She was immediately readmitted and a bone biopsy was performed. Her results with flow cytometry showed hypercellularity with 53% blast cells. The abnormal cells were positive for CD13 (58%), CD33 (73%), CD15 (59%), CD45, CD34, CD64, CD4, HLA DR, and MPO markers consistent with acute monocytic leukemia (FAB M5b). Refer to Figures
Rectal biopsy showing mucosal and submucosal atypical hematopoietic cell infiltration.
Anal ulcer biopsy showing atypical mucosal and submucosal hematopoietic cell infiltration.
Rectal ulcer biopsy under high magnification shows atypical large and medium hematopoietic cells with large irregular nuclei and pale cytoplasm. Scattered small lymphocytes and plasma cells also seen.
Immunohistochemical marker staining.
Bone marrow biopsy showing hypercellularity and atypical cells.
She was diagnosed with acute myeloid leukemia and started on high-dose Idarubicin and cytarabine for induction chemotherapy. Intrathecal methotrexate was also given as there was evidence of central nervous system disease. Her pregnancy was terminated therapeutically before the chemotherapy was started. A repeat bone marrow biopsy nine months later after completing chemotherapy did not show any atypical cells. She clinically has no evidence of disease at this time.
Myeloid sarcoma is a tumor composed of immature myeloid cells or myeloblasts at an extramedullary site often in close proximity to bone. Myeloid sarcoma can occur as a solitary mass or multiple nodules in different tissues or organs such as skin, bone, head and neck structures, oral cavity, gingiva, salivary glands, lymph nodes, central nervous system, and genital tract, and rarely in the gastrointestinal tract [
The involvement of the gastrointestinal tract in different hematologic malignancies occurs at an advanced stage of the disease or as a complication of chemotherapy and radiotherapy. The most common findings on endoscopy includes esophagitis, colitis, gastritis, gastric erosions, duodenitis, proctitis, and polyps [
Myeloid sarcoma poses a significant diagnostic challenge. Biopsy and staining with immunohistochemical markers play a vital role. The immunophenotype is characteristic based on whether myeloid sarcoma is granulocytic (MPO+, Lysozymes+, CD34+/−), monoblastic (MPO−, CD68+, Lysozyme−, CD34+), myelomonoblastic (MPO+/−, cd68+, lysozyme+/−, CD34+/−), megakaryoblastic (Factor VIII+, CD31+), or erythroblastic variant (glycoprotein c+) [
The patient in this report presented with anal pain which was initially presumed to be a fissure and treated accordingly. Her history of irritable bowel syndrome and her family history of inflammatory bowel disease gave the clinical impression of Crohn’s Disease with an atypical anal ulcer. An aggressive workup leading to admission and an examination under anesthesia led to the “confirmatory” diagnosis of anorectal Crohn’s Disease. The smear and histopathology with immunohistochemical markers diagnosed the myeloid sarcoma. A subsequent bone marrow evaluation, CSF analysis with flow cytometry, and cytogenetic studies confirmed the AML to allow initiation of treatment.
We did not find any association of pregnancy with increased incidence of myeloid sarcoma or acute myeloid leukemia in our review. Though, myeloid sarcoma was reported to involve the female genital tract [
It is unusual to find a diagnosis of myeloid sarcoma and AML with patients who present with common gastrointestinal problems. Our case illustrates the need for aggressive evaluation in any patient presenting with atypical gastrointestinal complaints.