Primary splenic histiocytic sarcoma associated with hemophagocytic lymphohistiocytosis: A case report and review of literature of next-generation sequencing involving FLT3, NOTCH2, and KMT2A mutations.

BACKGROUND: Histiocytic sarcoma is a very rare monocyte/macrophage-derived hematopoietic system tumor with a poor prognosis whose diagnosis is pathologically challenging due to its extreme rarity and histological overlap with various mimicking entities in which histiocytes also predominate. CASE: We report the case of a 33-year-old male patient with hemophagocytic lymphohistiocytosis, purpuric syndrome, and significant splenomegaly. The patient underwent splenectomy; subsequent macroscopic examination revealed a spleen weighing 2065 grams with hyperemic red pulp and multiple infarcts at the periphery. The histological and immunohistochemical study established a diagnosis of primary splenic histiocytic sarcoma with frequent hemophagocytosis. Next-generation sequencing demonstrated mutations in FLT3, NOTCH2, and KMT2A, microsatellite stability, and a tumor mutational burden of 2 mut/Mb. The patient's condition deteriorated clinically from the appearance of the first symptoms and he died 6 months later from multi-organ failure. CONCLUSION: Primary splenic histiocytic sarcoma is one of the rarest tumors of the hematopoietic system. We report the first case with mutations in FLT3, NOTCH2, and KMT2A, and associated hemophagocytic lymphohistiocytosis.

Wobbly hedgehog syndrome with disseminated histiocytic sarcoma and lateral ventricular meningioma in an African pygmy hedgehog.

An 8-mo-old male African pygmy hedgehog was anorectic and ataxic; physical examination revealed tetraparesis and a gangrenous left hindlimb. Analgesic and supportive care were administered, but the animal died 3 d after presentation. Postmortem examination revealed a histiocytic sarcoma in a mesenteric lymph node with metastasis to several organs, multifocal vacuolation in the cerebral and cerebellar white matter, and a meningioma in the left lateral ventricle. We diagnosed wobbly hedgehog syndrome (WHS) with disseminated histiocytic sarcoma and lateral ventricular meningioma. Ventricular meningioma, a rare neoplasm in veterinary and human patients, has not been reported previously in hedgehogs, to our knowledge. The neurologic signs in our case were probably caused by the WHS-related vacuolar lesions and are consistent with those of reported WHS cases. Duration of illness was shorter than is typical of WHS cases, which might be related to the disseminated histiocytic sarcoma. Clinical relevance of the lateral ventricular meningioma was not evident because the ventricular mass was localized and not invasive.

Extranodal histiocytic sarcoma mimicking colorectal lymphoma: Case report and review of literature.

Histiocytic sarcoma is a rare malignant neoplasm that demonstrates mature histiocytic traits as characterized by immunohistochemistry. We report a case of extranodal histiocytic sarcoma (ENHS) of colon in a 56-year-old man presenting with gastrointestinal symptoms. Radiological findings were indicative of lymphoma or diffuse metastatic disease in colon. Histopathology of colectomy specimen was suggestive of ENHS, and immunohistochemical studies confirmed the uncommon diagnosis. The patient refused further therapy and succumbed to systemic complications of metastatic disease within a month of diagnosis. There have only been seven previous reports in world literature of ENHS involving large intestine.

[Primary histiocytic sarcoma of the aortic valve as a trigger of heart failure in a crossbreed dog]. / Primäres histiozytäres Sarkom der Aortenklappe als Auslöser von Herz­versagen bei einem Mischlingshund.

INTRODUCTION: A case of a histiocytic sarcoma at the aortic valve with multiple metastases in the ventricular myocardium, ventricular endocardium and mitral valves in a male crossbreed dog is described. Neoplasia resulted in intermittent forward heart failure, thrombosis, myocardial infarction, and ventricular tachycardia.

INTRODUCTION: On décrit le cas, chez un chien croisé, d'un sarcome histiocytaire de la valvule aortique avec de multiples métastases dans le myocarde ventriculaire, l'endocarde ventriculaire et la valvule mitrale. Le néoplasie conduisait à une faiblesse, à des thromboses et des infarctus du myocarde ainsi qu'à une tachycardie ventriculaire.

Syndrome of inappropriate antidiuretic hormone secretion in a dog with a histiocytic sarcoma.

A 7-year-old female neutered Bernese mountain dog was presented in a semi-comatose state. Based on serum hypo-osmolality with inappropriate urine hyper-osmolality and urine sodium excretion, the dog was diagnosed with a syndrome of inappropriate antidiuretic hormone secretion secondary to a histiocytic sarcoma. This report describes the first case of this syndrome in a dog with histiocytic sarcoma.

Syndrome de sécrétion inappropriée d'hormone antidiurétique chez un chien avec un sarcome histiocytaire. Une chienne stérilisée de 7 ans, Bouvier bernois, est présentée dans un état semi-comateux. Basé sur une hypo-osmolalité sérique associée à une hyper-osmolalité urinaire et une excrétion sodique urinaire toutes deux inappropriées, un diagnostic de syndrome de sécrétion inappropriée d'hormone antidiurétique secondaire à un sarcome histiocytaire est posé. Ce cas est le premier cas de ce syndrome chez un chien avec un sarcome histiocytaire.(Traduit par les auteurs).

Primary histiocytic sarcoma of the uterine cervix: an extremely rare entity.

OBJECTIVE: Histiocytic sarcoma (HS) is an extraordinary rare tumor and it has an offensive clinical course. HS of the uterine cervix is a far uncommon tumor with just a few cases described so far. Here we presented a case of primary HS of the uterine cervix in a 62-year-old female initially misdiagnosed as large cell non-keratinizing squamous cell carcinoma. To the best of our knowledge, this is the first reported case of HS of the uterine cervix from Iran. CASE REPORT: The patient presented with post-menopausal vaginal bleeding. Further evaluations revealed the presence of a relatively large cervical mass that was sampled. Under the preliminary diagnosis of large cell non-keratinizing squamous cell carcinoma, the patient underwent radical surgery. Postoperative pathological examination confirmed the diagnosis of HS of the uterine cervix. The patient received chemotherapy. CONCLUSION: Clinical presentations of HS of the uterine cervix are very similar to more common cervical tumors; as a result its diagnosis relies on immunohistochemical methods. A correct diagnose could lead to the proper and timely treatment.

Sudden unexpected death from an undiagnosed histiocytic sarcoma in an adolescent female.

A previously well 15-year-old female who was awaiting medical investigations for a proptosed right eye collapsed and died suddenly while walking. Postmortem examination revealed diffuse distortion and infiltration of multiple organs by a suspected neoplastic process. Histology confirmed the invasion of multiple organs by atypical cells and myocardial infiltration was the likely cause of death. An extensive panel of immunohistochemistry established the diagnosis of a histiocytic sarcoma. Sudden unexpected death due to a clinically undiagnosed neoplasia in childhood and adolescence is uncommon. This is the first report of a histiocytic sarcoma causing sudden unexpected death and highlights the importance of considering undiagnosed hematological malignancies when examining a case of sudden death at postmortem.

UNUSUAL CLINICAL CASES THAT MIMIC ACUTE DISSEMINATED ENCEPHALOMYELITIS.

Acute disseminated encephalomyelitis (ADEM) is an immune-mediated monophasic inflammatory demyelinating disorder of the central nervous system which poses a diagnostic challenge. We report on six cases of different etiologies that mimicked the clinical and radiologic findings of ADEM. The cases were collected from four different reference hospitals in Turkey. The same radiologist from the Akdeniz University Faculty of Medicine examined the magnetic resonance images of all patients. Three (50%) patients had antecedent infections. Initial symptoms of the patients were as follows: fever in 50%, altered consciousness in 33.3% and convulsions in 16.7% of patients. Neurologic examination showed long tract signs in 83.3%, ataxia in 50% and altered consciousness in 50% of patients. Cerebrospinal fluid examination revealed lymphocytic pleocytosis only in case 6. Four patients received steroid pulse therapy and one of these initially underwent intravenous immunoglobulin therapy. The patients' definitive diagnoses were as follows: paraspinal neuroblastoma-associated paraneoplastic syndrome; histiocytic sarcoma; mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes; and cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy in one patient each, while two patients had hemophagocytic syndrome. The present case series demonstrated difficulties in diagnosing ADEM while revealing extremely rare disorders that mimic ADEM radiologically and clinically.

Concomitant follicular lymphoma and histiocytic sarcoma: A rare progression, trans-differentiation or co-occurrence?

Trans-differentiation of follicular lymphoma (FL) into a histiocytic sarcoma (HS) is a rare event and usually occurs as a sequential event. We report a case where in the same node with two distinct areas one of low-grade FL and another with HS was observed. This patient was a 58 years old with generalized lymphadenopathy and Ann Arbor Stage III disease. The cervical node biopsy on histological examination revealed two distinct areas, firstly a FL with nodular architecture and the other a smaller focus of sheets of pleomorphic histiocytic cells diffusely arranged at the edge of the section contiguous with FL with few cells in transiting phase. On immunohistochemistry the FL was positive for CD20, CD10, PU.1, PAX5 and Bcl2, while the large histiocytic cells were positive for CD163, CD68, LCA, and PU.1, weakly for PAX5 and negative for CD20, CD10, CD30, CD3, CD1a, Bcl2, S100, and Alk-1. The therapeutic implications of this diagnosis and postulated theories on trans-differentiation are discussed.

Isolated III cranial nerve palsies may point to primary histiocytic sarcoma.

Primary histiocytic sarcoma (HS) of the central nervous system (CNS) is a rare haematopoietic neoplasm. The inconsistent terminology and diagnostic criteria currently used for CNS HS have complicated the appreciation of the clinical aspects of the disease. The main differential diagnoses are non-Hodgkin's lymphoma, reactive histiocytic proliferation, dendritic cell neoplasm, undifferentiated carcinoma, inflammatory pseudotumour, Rosai-Dorfman disease and abscess. The true diagnosis of CNS HS requires an extensive immunophenotypic workup using specific histiocytic markers, such as CD163, with the exclusion of markers of other cell lineages. This clinicopathological case report describes an improved approach towards the differential diagnosis of CNS HS.