UNASSIGNED: Hairy cell leukaemia (HCL) is an uncommon, indolent, B-cell, lymphoproliferative disorder typically involving peripheral blood, spleen and bone marrow. It is commonly presenting with pancytopenia, monocytopenia and massive splenomegaly, while accounting for 2% of lymphoid leukaemias. Cases of extranodal lesions caused by HCL are rare, although these have been reported. Here, we report a case of HCL presenting as a paravertebral mass without systemic involvement.
UNASSIGNED: A 58-year-old man was admitted to our hospital due to progressive difficulty walking for a month, without any other symptoms. Blood examination noted mild anaemia with Hb=12.6 g/dl and mild thrombocytopenia of 140,000/μl. Magnetic resonance imaging (MRI) and computed tomography (CT) imaging demonstrated a T6 posterior paravertebral mass lesion, extending into the spinal canal with metastatic bone lesions along the thoracic and lumbar spine. Further imaging study with CT indicated mild splenomegaly (13.4 cm) and an enlarged abdominal lymph node (3.5 cm) near celiac trifurcation.
UNASSIGNED: A core-needle biopsy from the paravertebral mass was performed. Results showed small-sized cells with round or oval nuclei, and pale cytoplasm with immunophenotype: B-cell origination with CD20+, Cyclin D1+, DBA.44+, Annexin+ and BRAF+, indicative of HCL.
CONCLUSIONS: Hairy cell leukaemia (HCL) is relatively uncommon, accounting for 2% of all leukaemia cases.Extramedullary and skeletal involvement in HCL is rare and shares morphological characteristics with other peripheral small B-cell lymphoma neoplasms.Spine biopsy is essential for diagnosis in these cases, since it is always helpful to narrow the differential diagnosis.Correct diagnosis is essential for treatment of HCL and leads most patients to clinical remission and sometimes long-term cures.

A 72-year-old female presented with 2 years of pro-gradient pain in the upper thoracic spine radiating to the left arm and leg. MRI revealed a 2.7 × 2.0 × 12 cm paravertebral mass at T2/T3, extending into the foraminal and epidural nerves with extensive dural sac contact in the left hemithorax. The removed tumour was surprisingly soft for a schwannoma or chordoma. However, after the surgery, histopathology revealed the presence of brachyury protein (T-box transcription factor T), which is characteristic of a chordoma. While chordomas are extremely rare, it is important that they are kept in mind for the differential diagnosis of a posterior mediastinal mass. Successful treatment can only be achieved through a complete en bloc resection. This can often be complex due to their location along the spine. This case report aims to highlight the features and treatment of this rare disease.

BACKGROUND: Pneumocystis jirovecii infection is the most common opportunistic infection that causes pneumonia in human immunodeficiency virus (HIV)-infected patients; however, extrapulmonary P. jirovecii infection is extremely rare after the use of antiretroviral therapy. Here, we present the second reported case of paraspinal mass caused by P. jirovecii infection in an advanced HIV-infected patient.
METHODS: A 45-year-old woman presented with dyspnea on exertion, and significant weight loss within the preceding 4 months. Initial complete blood count (CBC) findings revealed pancytopenia with a hemoglobin (Hb) level of 8.9 g/dL, a white blood cell (WBC) count of 2180 cells/mm3 with 68% neutrophils, and a platelet count of 106,000 cells/mm3. Anti-HIV was positive with an absolute cluster of differentiation 4 (CD4) count of 16 cells/ mm3. A computed tomography scan of the chest revealed an enhancing soft tissue mass-like lesion at the right paravertebral region (T5-T10 level) and a thick-walled cavity lesion at the left lower lung. A CT-guided biopsy of the paravertebral mass was performed and histopathology revealed granulomatous inflammation consisting of dense aggregates of epithelioid cells and macrophages, and scattered foci of pink foamy to granular materials amidst the granulomatous inflammation. Gomori methenamine silver (GMS) staining revealed thin cystic-like structures (ascus) that were observed to be morphologically consistent with P. jirovecii. Molecular identification and DNA sequencing from the paraspinal mass was 100% identical to P. Jirovecii. The patient was successfully treated with oral trimethoprim-sulfamethoxazole for 3 weeks and antiretroviral therapy (ART) with tenofovir (TDF), lamivudine (3TC), and dolutegravir (DTG). A follow-up CT scan of the chest at 2 months after treatment showed a decrease in sizes of both the paravertebral mass and the cavitary lung lesion.
CONCLUSIONS: Extrapulmonary pneumocystosis (EPCP) has become an extremely rare condition in HIV-infected patients after the widespread use of ART. EPCP should be considered in ART-naive HIV-infected patients suspected of having or diagnosed with Pneumocystis jirovecii pneumonia who present with atypical symptoms and/or signs. Histopathologic examination with GMS staining of affected tissue is necessary for the diagnosis of EPCP.

Secondary anemia in hemoglobinopathies like thalassemia can cause expansion of the bone marrow cavities because of compensatory marrow hyperplasia. This case demonstrates spontaneous osteonecrosis of the distal left femur in a patient with β-thalassemia that may be secondary to ischemic infarction secondary to occlusion of the microvasculature within the expanded cancellous bone. This subject was referred to Hazrat Rasool Akram Hospital because of fever, cough, and bone pain. In the CT scan she had scattered peripheral CGO in both lungs due to COVID-19 with two paravertebral masses due to extramedullary hematopoiesis. The patient had also generalized bone pain so the physician asked for a whole-body bone scan and incidentally, we found a cold lesion with a rim of increased uptake in the distal left femur that with bone biopsy it was consistent with osteonecrosis. This case illustrates the importance of performing a whole-body bone scan in β-thalassemia for the management of patients and diagnosis of occult osteonecrosis.

Ewing\'s sarcoma (ES) is the second most common osseous tumor in young patients after osteosarcoma. All primitive neuroectodermal tumors (PNET) and Askin tumors are members of Ewing\'s sarcoma family of tumors (ESFT), which all have aberrant translocations between the 11th and 22nd chromosomes. Only one in five cases of Ewing\'s sarcoma occurs as extraskeletal. In this report, we describe a young female with a palpable lump on her spine who presented with paravertebral and thoracic extraskeletal Ewing\'s sarcoma (EES). Over six months, the swelling gradually increased in size, and the patient reported episodes of episodic pain and fever. Examining the swelling, a non-reducible, non-tender ovoid lump measuring approximately 8 cm x 5 cm was found to have smooth margins and be slightly mobile. The use of magnetic resonance imaging (MRI) helped diagnose, plan surgical resections, assess neoadjuvant chemotherapy effectiveness, and detect local recurrences and metastatic spread of the tumor. The differential diagnosis of EES included embryonal rhabdomyosarcoma and lymphoma. The use of immunohistochemical markers further differentiated the diagnoses. In conclusion, it should be noted that EES, though rare, should be considered when evaluating soft tissue lumps of neoplastic characteristics, in children or adolescents. Considering the poor prognosis of this disease, early detection is essential. The MRI plays a vital role in diagnosing cancer, staging it locally, assessing response to neoadjuvant therapy, and identifying local recurrences and metastases.

Extramedullary hematopoiesis is common in chronic hemolytic anemias such as pyruvate kinase deficiency. It is commonly associated with hepatosplenomegaly or lymphadenopathy; however, it can rarely also present as a mass in the chest, abdomen, or paraspinal region. Here, we present a case of an adult patient with pyruvate kinase deficiency and history of splenectomy. He presented with sepsis and brisk leukocytosis secondary to pneumonia and was also found to have diffuse intraabdominal lymphadenopathy along with a paravertebral mass. The radiological findings raised concerns for a systemic lymphoproliferative disorder and there was a suggestion for further workup with a biopsy. However, given the patient\'s underlying pyruvate kinase deficiency, we hypothesized that the paravertebral mass is likely a result of extramedullary hematopoiesis in the setting of bone marrow stress from infection and ongoing hemolysis; thus, we decided against biopsy. Repeat imaging six weeks after the presentation showed resolution of the paravertebral mass, which consolidated our hypothesis. This highlights the importance of avoiding invasive diagnostic procedures in asymptomatic patients with chronic hemolysis who may present with diffuse mass lesions.