Recurrent intranodal palisaded myofibroblastoma with metaplastic bone formation

Axillary intranodal palisaded myofibroblastoma, a rare tumour at an unusual site, with literature review

Intranodal palisaded myofibroblastoma (IPM) arising in the axilla is an extremely rare, benign mesenchymal tumour. It is believed to originate from myofibroblast or smooth muscle cells and exhibits specific histopathological features. While there have been occasional cases of recurrence, no malignant transformation has been observed. We describe the case of a 35-year-old male presenting with an axillary mass. Histopathology revealed a tumour with a pseudo-capsule that contains compressed lymphoid tissue with spindle cells arranged in a palisade-like pattern and extravasation of red blood cells within the spindle cells. Additionally, amianthoid fibres and fuchsinophilic bodies are present. Immunohistochemical analysis typically was positive for SMA and cyclin D1, with a low proliferative index (Ki67 of <1%). The diagnosis was intranodal palisading myofibroblastoma. Only two cases of IPM in the axilla have been previously reported. Pathologists should keep this rare entity with characteristic histopathological findings in mind when reporting such tumours at an unusual site.

Intranodal palisaded myofibroblastoma in the submandibular gland region: a case report

Intranodal palisaded myofibroblastoma (IPM) is a rare benign tumor of the lymph nodes, particularly in inguinal lymph nodes. IPM originating from the submandibular gland lymph nodes is rarely encountered in clinical practice. Herein, we report the case of a 31-year-old male patient with IPM of the submandibular gland region and describe in detail magnetic resonance imaging findings and pathology. Magnetic resonance imaging detected a heterogeneous lesion with a hypointense rim on T2-weighted imaging with specificity in the left submandibular gland region. This case report will contribute to the accumulation of experience in the diagnosis of this disease.

Intranodal Palisaded Myofibroblastoma in a Submandibular Lymph Node

Intranodal palisaded myofibroblastoma (IPM), also known as "intranodal hemorrhagic spindle cell tumor with amianthoid fibers," is a rare benign mesenchymal tumor originating from smooth muscle cells and myofibroblasts, often with the presence of amianthoid fibers. Usually IPM affects inguinal lymph nodes, but three cases have been described in the submandibular and cervical lymph nodes. We report a new case of a 44-year-old women with submandibular mass. Cervical ultrasound showed a suspect right submandibular adenomegaly. The patient underwent an excision of the submandibular mass. Histological features of the tumor include an encapsulated fusocellular proliferation, with nuclear palisading, amianthoid fibers, hemosiderin pigment, and extravasated erythrocytes. In the light of these results, we made the diagnosis of IPM. No recurrence was found 5 years after surgery.

Lymph node stromal and vascular proliferations

The recognition and reporting of stromal and vascular lesions of the lymph node is rife with difficulties including relative rarity, a lack of familiarity with lesions and the challenges of using ancillary studies appropriately. In this manuscript, we highlight a range of benign stromal and vascular abnormalities that can be identified in nodal specimens.

Diagnostic clues for FNA diagnosis of intranodal palisaded myofibroblastoma, a rare benign lesion, an introspective case report

Intranodal palisaded myofibroblastoma (IPM) is a benign entity, characterized by intranodal proliferation of cells of myofibroblastic origin. It has five distinct histologic features: compressed remnants of lymphoid tissue at the periphery, spindle cells with nuclear palisading, intralesional hemorrhage, amianthoid fibers, and intracellular and extracellular fuchsinophilic bodies. The spindle cells are SMA and vimentin (IHC) positive and are negative for S 100, and has a low proliferative index. Cytologic diagnosis of this lesion is a diagnostic challenge and has to be differentiated from other stroma rich lesions including schwannoma. The FNA smears were reviewed after histopathology to look for any specific features. This report highlights the variable character of spindle cells, presence of unique "amanthiod fibers" and blood vessel within cell clusters in MGG stained FNA smears, which can be a useful diagnostic clue. This observation is being reported for the first time.

Intranodal palisaded myofibroblastoma: another mesenchymal neoplasm with CTNNB1 (β-catenin gene) mutations: clinicopathologic, immunohistochemical, and molecular genetic study of 18 cases

Intranodal palisaded myofibroblastoma is a benign, lymph node-based myofibroblastic tumor of unknown pathogenesis. We report the clinicopathologic, immunohistochemical, and molecular genetic features of this rare entity. The study cohort consisted of 14 men and 4 women ranging in age from 31 to 65 (mean, 47; median 49) years with tumors arising in inguinal lymph nodes (n=15), a neck lymph node (n=1), and undesignated lymph nodes (n=2). Most individuals presented with a painless mass or lump. Possible trauma/injury to the inguinal region was documented in 4 cases. Tumors ranged in size from 1.0 to 4.2 (mean, 3.1; median; 3.0) cm. Microscopically, the process presented as a well-circumscribed, oftentimes pseudoencapsulated nodule (n=17) or nodules (n=1). Tumors consisted of a cellular proliferation of cytologically bland, spindled cells arranged in short fascicles and whorls within a finely collagenous (n=11) or myxocollagenous (n=7) matrix. In 12 tumors, scattered fibromatosis-like fascicles of spindled cells were noted. Histologic features characteristic of the process included nuclear palisades (n=16 cases), collagenous bodies (n=15), and perinuclear intracytoplasmic hyaline globules (n=10). Mitotic activity ranged from 0 to 8 (mean, 2; median, 1) mitotic figures/50 high-powered fields with no atypical division figures identified. Immunohistochemically, all tumors tested expressed smooth muscle actin and/or muscle-specific actin (n=5, each), and nuclear β-catenin and cyclin D1 (n=8, each). The latter 2 results prompted a screening for mutations in the β-catenin gene glycogen synthase kinase-3 β phosphorylation mutational "hotspot" region in exon 3 using polymerase chain reaction amplification and Sanger sequencing. Single nucleotide substitutions leading to missense mutations at the protein level were identified in 7 of 8 (88%) analyzed tumors and are responsible for the abnormal expression of β-catenin and cyclin D1. These results demonstrate that mutational activation of the β-catenin gene is likely a pivotal event in the pathogenesis of intranodal palisaded myofibroblastoma.

Intranodal palisaded myofibroblastoma: a review of the literature

Intranodal palisaded myofibroblastoma is a rare benign primary mesenchymal neoplasm originating from differentiated smooth muscle cells and myofibroblasts. The precise etiology and pathogenesis has not been adequately explained as yet. Very few series and cases have been reported in the literature. Though inguinal region is the commonest site of this rare tumor, but the tumor at other diverse sites have been reported. Because of its rarity, it can be often misdiagnosed and confused with other disorders and more commonly with metastasis. We report an extensive review of literature about intranodal palisaded myofibroblastoma--its characteristics, presentations, features, and management.

Myofibroma, Myopericytoma, Myoepithelioma, and Myofibroblastoma of Skin and Soft Tissue

The authors address a group of loosely associated, characteristically benign soft tissue neoplasms that exhibit partial myoid differentiation. The entities share similarities in morphology and in nomenclature that have historically created confusion. The authors attempt to clarify the distinct architectural patterns and the corresponding immunophenotypic and ultrastructural features that distinguish myofibroma, myopericytoma, myoepithelioma, and myofibroblastoma.

Intranodal palisaded myofibroblastoma originating from retroperitoneum: an unusual origin

BACKGROUND

Intranodal palisaded myofibroblastoma is one of the primary mesenchymal tumours. The inguinal region is the commonest site of this rare tumour. As there are only about 55 such cases reported in the literature, the precise aetiology and pathogenesis have yet to be explained adequately. Here we report a case of a 72 year old man presented with incidental finding of intranodal palisaded myofibroblastoma in the retroperitoneal region.

CASE PRESENTATION

A 72-year old man presented with abdominal pain in right upper quadrant with an incidental finding of abdominal mass in the right flank. The computerised tomogram scan of abdomen confirmed acute cholecystitis with a 5 x 5 cm retroperitoneal mass. He underwent cholecystectomy with excision of this mass. He recovered well following his operation and was discharged from the hospital. Histological examination confirmed the diagnosis of intranodal palisaded myofibroblastoma.

CONCLUSION

To our knowledge, this is the first case of intranodal palisaded myofibroblastoma originating from retroperitoneum. Along with the rarity of this case, we also discussed its typical histopathological findings, aetiology and pathogenesis.

Intranodal palisaded myofibroblastoma; a case report and review of the literature

Intranodal palisaded myofibroblastoma (IPM) also called as intranodal hemorrhagic spindle cell tumor with amianthoid fibers is a distinctive and rare mesenchymal neoplasm of lymph nodes. This entity generally misdiagnosed as intranodal Kaposi's sarcoma or schwannoma in past. In contrast to Kaposi's sarcoma, it behaves in a benign fashion and does not need any further therapy except total surgical resection of the mass. This neoplasm has a great predilection for the inguinal region. The lesion presents typically as a unilateral, painless, solitary mass. To our knowledge, approximately 53 cases of IPM have been reported in the English-language literature. We present a 43-year-old-male patient with IPM and discuss histological, immunohistochemical features and pathogenesis of this rare benign neoplasm.

Intranodal palisaded myofibroblastoma

Intranodal palisaded myofibroblastoma (IPM) usually presents as a painless, slow-growing inguinal mass. Our review of 42 cases from 13 publications indicates that two thirds of IPMs occur between the ages of 45 and 55 years, the male-female ratio is 2:1, and there is a lack of ethnic predilection. Grossly, the IPM cut surface shows areas of hemorrhage. Five microscopic features are seen: (a) compressed remnants of lymphoid tissue at the periphery; (b) spindle cells with nuclear palisading; (c) intraparenchymal hemorrhage and erythrocyte extravasation; (d) so-called amianthoid fibers; and (e) intracellular and extracellular fuchsinophilic bodies that stain positive for smooth muscle actin. Immunohistochemically, IPM is positive for smooth muscle actin and cyclin D1 and negative for S100, glial fibrillary acidic protein, CD34, and desmin, and it shows a low proliferative index of Ki-67. Electron microscopy demonstrates features of myofibroblasts and smooth muscle cells. Excellent prognosis is seen after surgical treatment, with an approximately 6% recurrence rate and no malignant transformation.

Intranodal palisaded myofibroblastoma with overexpression of cyclin D1

Intranodal palisaded myofibroblastoma (IPM) is a rare benign spindle-cell tumor of lymph nodes with myofibroblastic/smooth muscle differentiation. We present another case of IPM that confirms the myofibroblastic differentiation of the tumor cells and identifies the so-called amianthoid fibers as collagen deposits by immunohistochemical and ultrastructural techniques. Because IPM shares histomorphologic characteristics with an inflammatory myofibroblastic tumor that has been associated with a virus-induced alteration of cell cycle regulation, the diagnostic approach was extended in this case. We were able to demonstrate cyclin D1 overexpression but could detect neither amplification of the CCND1 gene nor allelic loss at chromosomes 9p22-21 and 13q (surrounding the genes p16 and Rb, respectively). Furthermore, no evidence of human herpesvirus-8 or Epstein-Barr virus infection could be found by polymerase chain reaction or immunostaining. Nevertheless, our results point to the cell cycle regulatory genes as a factor in the pathogenesis of IPM.