Spindle cell lipoma with extramedullary haematopoiesis

Spindle Cell Lipoma and Pleomorphic Lipoma in the Head and Neck: A Comprehensive Study of Six Cases With Review of Literature

BACKGROUND

Spindle cell lipomas (SL) and pleomorphic lipomas (PL) are rare variants of lipomas, occurring predominantly in the head and neck region. Laryngeal SL/PL is very uncommon and causes obstructive symptoms needing immediate intervention. These tumors are often challenging in radiology due to the admixture of elements and the presence of adipose tissue may help in diagnosis. From a surgeon's perspective, understanding the nuances of SL/PL is paramount. Histology is the gold standard for diagnosis; however, it often causes diagnostic challenges in biopsy.  Method: A retrospective review of the clinical and pathologic features of archival cases of SL/PL was performed.

RESULTS

A total of six cases of head and neck region SL/PL were identified. The age of patients ranged from 21 to 58 years and the male-to-female ratio was 5:1. The tumors were distributed in the nape of the neck (n=3), laryngeal region (n=2), and orbit (n=1). Histology in all the cases showed a low-grade neoplasm composed of a variable amount of spindle cells and adipose tissue. The stroma was myxoid in most cases. CD34 was diffusely positive in all the cases.

CONCLUSION

SLs are a rare and uncommon variant of lipoma with a predilection in the head and neck region. They are low-grade neoplasms with a propensity to recur after years. Having knowledge of this tumor can improve surgical outcomes and better patient care.

Paratesticular Extramedullary Hematopoiesis in Children

CONTEXT.—

Extramedullary hematopoiesis (EMH) is an uncommon occurrence, usually associated with hematologic disorders, but it rarely presents as an isolated finding.

OBJECTIVE.—

To determine the frequency, immunomorphologic features, and clinicopathologic background of EMH in orchiectomies from pediatric patients.

DESIGN.—

All orchiectomy specimens removed from children from 2008 to 2020 in our institution were retrospectively reviewed. Biopsies and neoplasias were excluded. The EMH diagnosis was rendered when hematopoietic cell precursors were present. Immunohistochemical stainings were performed to characterize the hematopoietic components.

RESULTS.—

Seventy-nine orchiectomies from 77 children (mean age, 5 years; range, 0-17 years) were included in our study. Forty-three patients (55.8%) underwent surgery for testicular atrophy, 30 (39.0%) for torsion, and 4 (5.2%) for intersex conditions. EMH was identified in 6 of 79 orchiectomies (7.6%), all performed for testicular torsion. All patients but one were newborns, and the remaining patient was 15 years old. No patient had evidence of a hematologic disorder. All EMH foci were in a background of reactive changes with a variable extension, either in the epididymis (4 cases) or in the deferens duct (2 cases). Immunostaining confirmed an association of myeloid (myeloperoxidase+) and erythroid precursors (E-cadherin+) in all 6 cases. One case also presented rare megakaryocytes, and one showed benign TdT+ B-cell precursors.

CONCLUSIONS.—

To our knowledge, this is the first study that demonstrates EMH as a common finding in orchiectomy samples, especially from newborns. Despite the lack of pathologic potential, it is important to recognize EMH in order to avoid misdiagnosis.

Extramedullary Hematopoiesis: An Unusual Finding in Angiolymphoid Hyperplasia With Eosinophilia

Extramedullary hematopoiesis is the process of blood cell synthesis occurring outside the medulla of the bone marrow. During fetal development, extramedullary hematopoiesis is considered physiological; however, it is considered pathologic when occurring outside the neonatal period. Angiolymphoid hyperplasia with eosinophilia (ALHE) describes a lesion characterized histologically by plump endothelial cells associated with a mixed inflammatory infiltrate of lymphocytes, plasma cells, mast cells, and eosinophils. This report describes an adolescent boy with an isolated preauricular facial lesion. After excision, histopathology confirmed a diagnosis of ALHE with the additional finding of trilineage extramedullary hematopoiesis. To the authors' knowledge, this is the first reported case of extramedullary hematopoiesis in ALHE.

Intratumoral extramedullary hematopoiesis in solitary fibrous tumor of the breast

Extramedullary hematopoiesis (EMH) is most often associated with underlying hematologic disorders, such as myeloproliferative neoplasms and thalassemia. EMH in the setting of solitary fibrous tumor (SFT) is exceedingly rare, with only 3 cases reported to date in the English literature. Herein, we describe our experience with a unique case of SFT arising in the breast with intratumoral foci of EMH in a 57-year-old woman who presented with an incidentally found right axillary mass on routine screening mammography. To the best of our knowledge, this is the first reported case of mammary SFT with concurrent intratumoral EMH.

Pure erythropoiesis in clear cell renal cell carcinoma

Extramedullary hematopoiesis (EMH) is a phenomenon in which benign immature hematopoietic cells are found in sites other than the bone marrow. Although usually associated with an underlying hematologic abnormality such as myelofibrosis, it can be found in some physiologic states or occasionally within solid tumors. In most instances, foci of EMH contain elements of all cell lineages. Presented here is the second reported case of EMH occurring in a low-grade clear cell renal cell carcinoma in a patient without evidence of hematologic disease. As previously, it manifested as pure erythropoiesis as confirmed by morphology and immunohistochemistry. It is possible that this finding is related to erythropoietin secretion by the tumor and not hematologic malignancy.

Benign extramedullary myeloid proliferations

Extramedullary proliferations of bone marrow elements are infrequently encountered in routine pathology practice. On occasion, they can present diagnostic difficulties when seen in unusual or unanticipated sites. This review serves to cover aspects of underlying embryogenesis of myeloid elements, as well as sites and circumstance of benign proliferations of myeloid elements along with their occasional confusion with neoplastic myeloid proliferations. Benign proliferations associated with hematologic disorders and hematopoietic growth factors are discussed. Immunohistochemical evaluation of myeloid proliferations is considered as well.