Abstract
Myeloid sarcoma (MS) is a rarely encountered extramedullary localized tumor that is composed of immature myeloid cells. We reported an extremely rare case of MS with concurrent bone marrow (BM) involvement that invaded into a preexisting sebaceous lymphadenoma in the parotid gland and neck lymph nodes. Prompted by this case, we also present a literature review of MS invasion into salivary glands. A 62-year-old man was initially diagnosed with carcinoma that arose in a sebaceous lymphadenoma in the parotid gland, through a total parotidectomy with neck dissection. After an extensive histopathological review that included immunohistochemistry, a pathologic diagnosis of MS with infiltration into the sebaceous lymphadenoma with concurrent BM involvement was confirmed. MS is difficult to diagnose accurately; herein, we analyzed the clinical presentations and effectiveness of the various diagnostic methods with a review of the literature. There are 17 cases, including our case, reported in 13 studies. Of the cases in which the salivary glands were affected, 10 involved the parotid gland, six involved the submandibular gland, and one involved both. Isolated invasion of the salivary gland was found in one case of parotid gland invasion and three cases of submandibular gland invasion. In 13 cases, the salivary glands were affected by various other lesions. Although there were no incidences of isolated MS, six patients were diagnosed with secondary MS and eight patients with MS with BM involvement, including this case. The diagnosis of MS is difficult given its rarity, and a high index of suspicion and integrated radiologic and careful histopathologic evaluation are required. Most cases of MS infiltrating the salivary gland might be indicated by the possibility of BM involvement. MS with BM involvement predicts poor prognosis and the need for intensive systemic treatment.
Highlights
Myeloid sarcoma (MS), known as extramedullary myeloid tumor, granulocytic sarcoma, or chloroma, is a tumor that consists of myeloid blasts that effaces tissue architecture [1, 2]. e 2008 World Health Organization (WHO) classification clarified the diagnosis of MS as follows: “a tumor mass consisting of myeloid blasts with or without maturation occurring at an anatomic site other than the bone marrow (BM)” [1, 3, 4]
US, computed tomography (CT), and magnetic resonance imaging (MRI) demonstrated a 31 × 29 × 36 mm lobulated, nodular isodense, and necrotic mass that involved the superficial and deep lobes of the left parotid gland, and multiple homogenous densities and necrotic enlarged lymph nodes were found in both sides of the neck (Figures 1(a)–1(f)). ere were intense FDG-avid masses in the left parotid gland and multiple enlarged lymph nodes on both sides of the neck on positron emission tomography-CT (PET-CT) (Figure 2)
To confirm the pathologic diagnosis and guide treatment planning, we performed a repeat ultrasonography-guided core needle biopsy (US-CNB) of the parotid lesion and the neck lymph nodes that were highly suspected for malignancy in the radiologic study. e parotid mass diagnosis was consistent with a malignant salivary gland neoplasm, but the neck lymph nodes demonstrated benign lymphoid tissue
Summary
Myeloid sarcoma (MS), known as extramedullary myeloid tumor, granulocytic sarcoma, or chloroma, is a tumor that consists of myeloid blasts that effaces tissue architecture [1, 2]. e 2008 World Health Organization (WHO) classification clarified the diagnosis of MS as follows: “a tumor mass consisting of myeloid blasts with or without maturation occurring at an anatomic site other than the bone marrow (BM)” [1, 3, 4]. E 2008 World Health Organization (WHO) classification clarified the diagnosis of MS as follows: “a tumor mass consisting of myeloid blasts with or without maturation occurring at an anatomic site other than the bone marrow (BM)” [1, 3, 4]. MS has been described in 2.5–9.11% of patients with acute myeloid leukemia (AML) during the disease course [5, 6]. Patients with MS have a history of preexisting AML, MDS, or MPN [9]. Primary MS may occur de novo, concurrently with, or preceding the diagnosis of AML, and it constitutes 27% of all MS diagnoses [9, 10]. Isolated MS may present without any preexisting condition and a lack of BM involvement [9]
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