Localización atípica de un lipoblastoma en una niña de 5 años / Atypical location of lipoblastoma in a 5-year-old girl

Se informa de un lipoblastoma perineal en una niña de 5 años localizado en el labio mayor derecho. La lesión aumentó gradualmente en 6 meses. En la ecografía y la resonancia magnética (RM), se observó un tumor heterogéneo sólido limitado con componente graso. Tras su extirpación quirúrgica, el estudio anatomopatológico confirmó un lipoblastoma. El lipoblastoma es un tumor mesenquimatoso benigno poco frecuente de la lactancia y la primera infancia. Los síntomas varían en función de la localización; pueden observarse signos de compresión de los órganos adyacentes. Este tipo de tumores inusuales de los tejidos blandos son más frecuentes en menores de 3 años. Los lipoblastomas se localizan predominantemente en las extremidades, pero también pueden encontrarse en la cabeza y el cuello, el tronco, el mediastino, el riñón, el mesenterio, el retroperitoneo y el perineo. Se debe sospechar su presencia en función de los hallazgos de la ecografía y la RM.

We reported a perineal lipoblastoma in a 5-year-old girl located in the right labia mayor. The lesion gradually increased within 6 months. Ultrasound and magnetic resonance imaging (MRI) showed a limited solid heterogenous tumor with fatty component. After it had been surgically removed, the anatomopathological examination confirmed that it was a lipoblastoma. Lipoblastoma is a rare benign mesenchymal tumor of infancy and early childhood. Symptoms vary depending on localization; signs of compression of adjacent organs may be seen. This type of unusual soft tissue tumors occurred most often in under 3 years old. The localization of lipoblastomas is predominantly in the extremities but may be also found in other sites including the head and neck, trunk, mediastinum, kidney, mesentery, retropritoneum and perineum. The suspicion should be considered according to ultrasound and MRI findings.

Lipoblastoma Arising in the Head and Neck: A Clinicopathologic Analysis of 20 Cases.

BACKGROUND: Lipoblastomas (LPBs) are benign adipocytic neoplasms believed to recapitulate the development of embryonal fat. METHODS: We investigated the clinicopathologic and immunohistochemical features of 20 lipoblastomas arising in the head and neck in 18 patients. RESULTS: Patients included 6 males and 12 females (1:2 ratio) with age at diagnosis ranging from 4 months to 28 years. Tumors occurred more commonly in the neck (12, 66.7%) and less commonly in the forehead, scalp, and tongue (2, 11.1%). Tumor size ranged from 1.4 to 6.0 cm (median 5.0 cm). Two patients, a 4-month-old female and 3-year-old male, had local recurrence of neck tumors at 4 months and 3 years after excision, respectively. Microscopically, tumors had a lobulated growth pattern and consisted of adipocytes at varying stages of differentiation. In addition to the classical histologic features, lipoma-like and myxoid variants constituted 45% of cases. Metaplastic elements, including brown fat and cartilage, were identified in two cases. CONCLUSIONS: LPBs arising in the head and neck region are not uncommon and occurred at a rate of 9% in our cohort. They should be kept in the differential diagnosis when a fatty tumor is encountered in an older child or occurring at an unusual location.

Lipoblastomatosis Extended into the Lumbar Spinal Canal in a Child: A Case Report.

INTRODUCTION: Lipoblastoma and lipoblastomatosis are rare benign mesenchymal adipose tumors that originate from embryonic white adipocytes and occur most commonly in infancy and early childhood. Lipoblastomas occur in the extremities and trunk, including the retroperitoneum and peritoneal cavity. Therefore, infiltration into the spinal canal has rarely been reported. CASE PRESENTATION: A 4-year-old girl presented to our clinic because of difficulty sitting on the floor with her legs straight. She also complained of enuresis and constipation for the past 6 months with persistent headaches and back pain evoked by body anteflexion. A magnetic resonance imaging revealed a massive lesion of the psoas major muscle, retroperitoneal, and subcutaneous spaces, extending into the spinal epidural space between L2 and S1. The patient underwent surgery which resulted in gross total removal of the tumor from the spinal canal. The mass was yellowish, soft, lobulated, fatty, and easily removed from the surrounding structures. Pathology confirmed the diagnosis of lipoblastoma. The postoperative course was uneventful, and the patient was discharged without any signs of neurological deficit. CONCLUSION: We herein discuss a rare case of lipoblastoma extending into the spinal canal, resulting in neurological symptoms. Although this tumor is benign with no potential for metastasis, it is prone to local recurrence. Therefore, close postoperative observation should be performed.

Primary cardiac lipoblastoma of the right atrium.

Lipoblastoma is a rare neoplasm of the embryonal white fat. It occurs most commonly in children under the age of 3 years and usually inflicts the superficial soft tissues of trunk and extremities. We present the case of a 3-year-old male patient with a successfully resected primary cardiac right-atrial lipoblastoma with COL1A2::PLAG1 gene fusion.

Atypical location of lipoblastoma in a 5-year-old girl. / Localización atípica de un lipoblastoma en una niña de 5 años.

We reported a perineal lipoblastoma in a 5-year-old girl located in the right labia mayor. The lesion gradually increased within 6 months. Ultrasound and magnetic resonance imaging (MRI) showed a limited solid heterogenous tumor with fatty component. After it had been surgically removed, the anatomopathological examination confirmed that it was a lipoblastoma. Lipoblastoma is a rare benign mesenchymal tumor of infancy and early childhood. Symptoms vary depending on localization; signs of compression of adjacent organs may be seen. This type of unusual soft tissue tumors occurred most often in under 3 years old. The localization of lipoblastomas is predominantly in the extremities but may be also found in other sites including the head and neck, trunk, mediastinum, kidney, mesentery, retropritoneum and perineum. The suspicion should be considered according to ultrasound and MRI findings.

Se informa de un lipoblastoma perineal en una niña de 5 años localizado en el labio mayor derecho. La lesión aumentó gradualmente en 6 meses. En la ecografía y la resonancia magnética (RM), se observó un tumor heterogéneo sólido limitado con componente graso. Tras su extirpación quirúrgica, el estudio anatomopatológico confirmó un lipoblastoma. El lipoblastoma es un tumor mesenquimatoso benigno poco frecuente de la lactancia y la primera infancia. Los síntomas varían en función de la localización; pueden observarse signos de compresión de los órganos adyacentes. Este tipo de tumores inusuales de los tejidos blandos son más frecuentes en menores de 3 años. Los lipoblastomas se localizan predominantemente en las extremidades, pero también pueden encontrarse en la cabeza y el cuello, el tronco, el mediastino, el riñón, el mesenterio, el retroperitoneo y el perineo. Se debe sospechar su presencia en función de los hallazgos de la ecografía y la RM.

Metastatic lipoblastoma-like tumour.

INTRODUCTION: Lipoblastoma-like tumours (LLT) are uncommon and their biologic nature is not well-understood. Complete resection of the primary lesion is usually curative. This is the first reported case of metastatic LLT. CASE PRESENTATION AND MANAGEMENT: This patient originally had a large primary resected from the vulva. She subsequently developed tumours in multiple areas including her right pleura and lung. These were resected and pathology was consistent with LLT. On follow-up imaging, there was evidence of metastatic disease. CONCLUSION: The patient is currently undergoing detailed molecular analysis in the hope of detecting a molecular target. Given the infrequent occurrence of LLT, its behaviour is not well understood. Longer duration of follow up is required and prognostic markers need to be identified to better direct treatment.

Pediatric fibromyxoid tumor with PLAG1 fusion: An emerging entity with a novel intracranial location.

Translocations involving PLAG1 occur in several tumors, most commonly pleomorphic adenoma and lipoblastoma. Recently, a distinctive soft tissue tumor with a PLAG1 fusion has been reported in the pediatric age group. These are low grade tumors with a fibroblastic or mixed fibroblastic and myxoid morphology but no other lines of differentiation. They are typically immunopositive for desmin and CD34. The partner genes for these tumors have included YWHAZ, EEF1A1, ZFHX4l, CHCHD7, and PCMTD1. We report another case of this fibromyxoid tumor with a PLAG1 fusion, this time with COL3A1 as the partner gene. The fusion placed expression of a full-length PLAG1 protein under the control of the constitutively active COL3A1 promoter. Overexpression of PLAG1 was confirmed by diffusely positive immunostaining for PLAG1. The most novel aspect of this tumor is the intracranial location. Opinion has been divided over whether these tumors are a specific entity, or related to lipoblastoma, since that tumor also typically occurs in soft tissue in the pediatric age group and shows many of the same gene fusions. However, lipoblastoma has never been reported in an intracranial location and, thus, our case provides compelling evidence that this fibromyxoid tumor is indeed a distinct entity.

Intrascrotal Lipoblastoma: A Rare Cause of Paratesticular Mass in a Pediatric Patient.

There is a broad differential diagnosis for a pre-pubertal child presenting with a scrotal mass including both benign and malignant etiologies. Lipoblastomas are rare benign neoplasms originating from fat cells that occur most commonly on the trunk or extremities of young children. There have been less than 20 cases of scrotal lipoblastomas reported in the literature, with the majority occurring in children less than 3 years of age. Here we present a unique case of an 18-month male presenting with a paratesticular mass found to be a lipoblastoma on final pathology.

[Lipoblastoma-like tumor of the vulva: A case report and review of the literature]. / Tumor vulvar similar a lipoblastoma: descripción de un nuevo caso y revisión de la literatura.

Lipoblastoma-like tumor of the vulva (LBLTV) was first described as a benign mesenchymal neoplasia; it was not recognized as a separate diagnosis in the 2013 WHO classification of soft-tissue tumors. To date, only 19 cases have been reported. LBLTV differential diagnosis includes other tumors of the vulvoperineal region and tumors with adipocytic differentiation, most of which are benign and thus a misdiagnosis has few clinical consequences. However, LBLTV may also mimic some aggressive lipomatous neoplasms. We describe a case of LBLTV in a 28 year-old woman and review the literature.

Lipoblastoma of scalp in a 4-month-old patient: an extremely rare case report and review of the literature.

Lipoblastoma is a rare benign tumor originating from adipose tissue, usually seen in infancy and early childhood. Here, we present a case of scalp lipoblastoma in a 4-month-old that we treated surgically and review the literature. Although lipoblastomas may be seen in various locations during infancy and early childhood, rarely, they can also develop in the scalp.

The histological and molecular spectrum of lipoblastoma: A case series with identification of three novel gene fusions by targeted RNA-sequencing.

Lipoblastoma is a rare benign mesenchymal neoplasm that typically occurs in infancy but may also occur in older age groups and various locations. Thus, there are often numerous clinical differential diagnoses. Moreover, lipoblastomas can show a broad histologic spectrum, which can hamper the correct diagnosis, particularly in small biopsies. At the genomic level, lipoblastomas are characterized by chromosomal fusions involving the PLAG1 gene. We investigated 11 lipoblastoma samples from 10 pediatric patients (age range five months to 12 years), including one patient with local recurrence, in view of their histopathological features, and performed targeted RNA sequencing. We found a broad histological spectrum with some tumors with prominent myxoid changes, but also tumors composed mainly of mature adipocytic cells, and classified the cases according to the literature as classic (mixed), maturing, or myxoid subtype. By targeted RNA sequencing analysis, we identified characteristic PLAG1 rearrangements in 70% of the investigated cases. Moreover, these analyses revealed three novel gene fusions, two affecting the PLAG1 gene and one involving HMGA2. Besides, we performed PLAG1 immunohistochemistry and identified positive cells, typically immature adipocytic cells and spindle cells, at various numbers in all cases. However, in the maturing areas, only very sparsely positive cells were found, limiting the value of the PLAG1 immunohistochemistry as an adjunct in the diagnosis of lipoblastoma, particularly for the maturing subtype and small biopsies. The presented case series confirms the broad morphological spectrum of lipoblastoma described in the literature and underlines the value of modern molecular diagnostic approaches as a supportive diagnostic tool in challenging cases and for gaining further insights into the molecular basis of this rare mesenchymal tumor.

Lipoblastomas presenting in older children and adults: analysis of 22 cases with identification of novel PLAG1 fusion partners.

Lipoblastomas are benign neoplasms of embryonal white fat that typically present in the first 3 years of life and show a lobular arrangement of maturing adipocytes with variable degrees of myxoid change. We systematically studied the clinicopathologic and genetic features of lipoblastomas arising in older children and adults. Cases with a diagnosis of lipoblastoma or maturing lipoblastoma in patients >3 years of age were retrieved from our archives. Immunostaining for CD34 and desmin and molecular studies (FISH, RNA sequencing) were performed. Twenty-two cases (8F; 14M) were identified in patients ranging from 4 to 44 years of age (median 10 years). Sites included extremity (n = 15), head and neck (n = 4), and trunk (n = 3) with tumor sizes varying from 1.6 to 17.5 cm (median 5). Only three tumors had histologic features of "conventional" lipoblastoma. The majority of tumors (n = 14) were composed of variably sized lobules of mature adipose tissue partitioned by thin fibrous septa ("maturing"). The remaining five cases consisted predominantly of bland spindled to plump ovoid cells embedded in a fibrous stroma, with a vaguely plexiform arrangement of small myxoid and adipocytic nodules ("fibroblastic"). CD34 was diffusely positive in all cases tested (21/21), while desmin immunoreactivity was identified in 12 of 21 cases (diffuse = 7, focal = 5). PLAG1 rearrangements were identified in 13 tumors in the entire cohort (59%), including all 5 fibroblastic tumors. RNA sequencing detected eight PLAG1 fusion partners, of which two were known (CHCHD7 and COL3A1) and six were novel (SRSF3, HNRNPC, PCMTD1, YWHAZ, CTDSP2, and PPP2R2A). Twelve cases had follow-up (1-107 months; median 21 months), and no recurrences were reported. Lipoblastomas may occur in older children and adults and may be difficult to recognize due to their predominantly adipocytic or fibrous appearance. Awareness that lipoblastomas may occur in older patients, careful evaluation for foci showing more typical morphologic features, ancillary immunohistochemistry for CD34 and desmin, and molecular genetic studies to identify PLAG1 rearrangements are the keys to recognizing these tumors.

Lipoblastoma-like tumor of the spermatic cord: case report and review of the literature.

Lipoblastoma-like tumor is a very rare mesenchymal tumor believed to be restricted to female patients and only recently reported in the spermatic cord of a male patient. We describe herein an additional case of lipoblastoma-like tumor occurring in the spermatic cord, describing its histopathological, immunohistochemical, and molecular features.

New molecular insights into the pathogenesis of lipoblastomas: clinicopathologic, immunohistochemical, and molecular analysis in pediatric cases.

Lipoblastomas can occasionally require further molecular confirmation when occurring outside of the usual age groups or demonstrating unusual morphology. We reviewed 28 lipoblastomas with 16 controls. Lipoblastomas were subdivided into myxoid (n = 7), classic (n = 9), or lipoma-like (n = 12) subtypes. PLAG1 immunohistochemistry, PLAG1 fluorescence in situ hybridization (FISH), and targeted RNA sequencing were performed on formalin-fixed paraffin-embedded tissue. Karyotypes were available in a subset of lipoblastomas (n = 9). Gene rearrangements were identified in 17/25 (68%) lipoblastomas, including PLAG1 (15/25, 60%) and HMGA2 (2/25, 8%). Five novel fusion partners (DDX6, KLF10, and KANSL1L with PLAG1 and EP400 and FGD6 with HMGA2) were found. PLAG1 immunohistochemistry was positive (nuclear, moderate/strong) in myxoid and classic subtypes lipoblastomas with preferential expression in mesenchymal cells within myxoid stroma and fibrous septa and negative in all controls. When comparing PLAG1 immunohistochemistry with molecular testing (FISH and/or RNA sequencing and/or karyotype), concordant results were noted in 13/25 (52%) cases, increasing to 15/25 (60%) after slight adjustment of the PLAG1 FISH positive threshold. In myxoid and classic lipoblastomas, PLAG1 immunohistochemistry seems to be a better surrogate marker for PLAG1 rearrangement, as compared with lipoma-like subtypes. In lipoma-like subtypes, targeted RNA sequencing appears to detect PLAG1 fusions better than FISH and immunohistochemistry. The preferential expression of PLAG1 in the mesenchymal and fibroblast-like cells deserves further investigation as the putative cell of origin in lipoblastoma.

Lipomatous Tumors in Pediatric Patients: A Retrospective Analysis of 50 cases.

OBJECTIVE: Although lipomatous tumors are the most common type of mesenchymal tumors in adults, they account for less than 10% of all soft tissue lesions in pediatric patients. In this descriptive study, we aim to present our series of pediatric lipomatous tumors consisting of lipoma, neural fibrolipoma, lipoblastoma, atypical lipomatous tumor, myxoid liposarcoma and pleomorphic liposarcoma, and to evaluate the clinicopathological characteristics of these tumors in reference to the literature. MATERIAL AND METHOD: In this study, pediatric lipomatous tumor cases diagnosed between 2002 and 2018 were screened from pathological archives and retrospectively evaluated. RESULTS: A total of 50 cases were diagnosed with lipomatous tumor within the mentioned period. Of the total cases, 24 were female (48%) and 26 were male (52%), with age distribution ranging from 1 to 204 months. Histopathological examination revealed lipoma in 26 cases (52%), lipoblastoma in 19 (38%), atypical lipomatous tumor in 2 (4%), myxoid liposarcoma in 2 (4%), and pleomorphic liposarcoma in 1 case (2%). CONCLUSION: Although lipomatous tumors are the most common type of mesenchymal tumors; they rarely occur in children. Since there is a limited number of studies on pediatric lipomatous tumors in the literature, there is insufficient data on the prevalence and incidence of these tumors. These tumors may slowly enlarge to greater sizes, especially those localized in deep tissues, and may cause various clinical symptoms by compressing surrounding tissues. Local recurrences may occur, even after total excision, and require close monitoring.