| Abstract|| |
Pseudomyogenic hemangioendothelioma (PHE) is an uncommon, but distinctive soft tissue tumor, characterized by multifocality. A 17-year-old male referred to us with progressively increasing multiple subcutaneous nodular lesions over his left leg and foot, reported elsewhere as a spindle cell rhabdomyosarcoma. On review, microscopy showed a cellular tumor comprising plump spindle cells arranged in loose fascicles with interspersed inflammatory cells. Tumor cells exhibited mild nuclear variation. Immunohistochemically, tumor cells expressed AE1/AE3, CD31, Fli-1, and smooth muscle actin (SMA), confirming diagnosis of PHE. Whole-body positron emission tomography–computed tomography (PET-CT) scan revealed multiple, metabolically active, subcutaneous nodular lesions over the left lower leg and in the distal tibia. Subsequently, resection specimens from the various lesions and bone curettage also revealed features of PHE. Three months later, the patient developed multiple lesions over his fourth toe and left foot, for which he underwent tumor resections. At present, he is disease-free. PHE is a locally aggressive soft tissue tumor characterized by multifocality, rarely bony involvement and can be misdiagnosed as a high-grade sarcoma.
Keywords: CD31, epithelioid sarcoma-like hemangioendothelioma, Fli-1, pseudomyogenic hemangioendothelioma, uncommon soft tissue and bone tumors
|How to cite this article:|
Rekhi B, Gulia A, Rangarajan V. A rare case of multifocal pseudomyogenic hemangioendothelioma, involving soft tissues and bone, misdiagnosed as a rhabdomyosarcoma: Diagnostic and treatment implications. Indian J Pathol Microbiol 2016;59:382-5
|How to cite this URL:|
Rekhi B, Gulia A, Rangarajan V. A rare case of multifocal pseudomyogenic hemangioendothelioma, involving soft tissues and bone, misdiagnosed as a rhabdomyosarcoma: Diagnostic and treatment implications. Indian J Pathol Microbiol [serial online] 2016 [cited 2019 Aug 24];59:382-5. Available from: http://www.ijpmonline.org/text.asp?2016/59/3/382/188144
| Introduction|| |
Pseudomyogenic hemangioendothelioma (PHE) is a distinctive, rarely metastasizing endothelial-derived mesenchymal tumor, occurring most frequently in young adult males, characterized by multiple discontinuous nodules in various tissue planes of a limb. Histopathologically, PHE comprises plump spindle cells and mimics an epithelioid or a myoid/muscle tumor., This can lead to over diagnosis of rhabdomyosarcoma in such cases, especially in the absence of relevant immunohistochemistry. Less than 20 cases of PHE have been documented involving the bones.,,,,,,,
| Case Report|| |
A 17-year-old male referred to us with a history of trauma 8 months back ever since he noticed progressively increasing nodular cutaneous lesions over his left leg.
On clinical examination, multiple subcutaneous nodular lesions were noted over his left shin (tibia), lateral side of leg, and calf [Figure 1]a. In addition, he had a small papular lesion on the dorsal aspect of fourth toe and on the plantar aspect of his left foot.
|Figure 1: (a) Clinical photograph showing multiple subcutaneous nodular lesions over left shin (tibia) and lateral side of left leg. (b) Magnetic resonance imaging displaying hyperintense subcutaneous lesion (arrowhead) in the left lower leg. (c) Computed tomography scan showing a lytic lesion (arrowhead) in the left tibia. (d). Histopathological findings. Cellular spindle cell tumor below the epidermis (H and E, × 100). (e) Plump, spindle-shaped tumor cells containing abundant eosinophilic cytoplasm and interspersed inflammatory cells (H and E, × 200)|
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Whole-body, fluorine-18 -fluorodeoxyglucose (18F-FDG) positron emission tomography–computed tomography (PET-CT) scan revealed multiple, metabolically active, FDG-avid subcutaneous lesions over the medial and lateral aspect of his left lower leg (largest measuring 1.5 cm, SUVmax= 10.86) – another lesion in his left calf muscles (2 cm, SUVmax= 11.35) and a lytic lesion in his distal left tibia with a soft tissue component (1.4 cm, SUVmax= 11.54) [Figure 1]b and [Figure 1]c. There were no metastatic lesions in his body. He underwent a biopsy elsewhere that was reported as spindle cell rhabdomyosarcoma. Subsequently, he underwent multiple resections of the various nodules and bone curettage at our institution.
During gross examination, the skin covered soft tissue mass containing anterolateral lesions measured 10.5 cm × 5.6 cm × 1.3 cm. On serial sectioning, several nodular areas were identified, largest measuring 2.5 cm × 2.5 cm × 1.7 cm. Another soft tissue mass with a skin flap containing the superomedial lesion on serial sectioning displayed a nodular lesion measuring 1.6 cm × 1.5 cm × 1.5 cm. A soft tissue mass containing lesion over Achilles tendon measured 4.5 cm × 2.5 cm × 1.5 cm and, on serial sectioning, revealed a lesion measuring 2.2 cm × 1.7 cm × 1.1 cm. Distal tibial curettage specimen measured 3 cm × 1.5 cm × 1.5 cm.
Histopathologic sections from various lesions showed a multinodular cellular tumor below epidermis, infiltrating the subcutaneous fat, comprising plump spindle to polygonal cells with abundant eosinophilic cytoplasm, arranged in loose fascicles. Cells exhibited mild nuclear variation without anaplasia. Interspersed were inflammatory cells. There were no significant mitoses or areas of tumor necrosis [Figure 1]d and [Figure 1]e. Immunohistochemically, tumor cells were positive for pan CK (AE1/AE3), CD31, SMA, diffusely positive for Fli-1, while negative for CD34, desmin, myogenin, myoD1, p63, and S100P. INI1/SMARCB1 was retained. Ki67 highlighted 20–25% tumor cells [Figure 2]a, [Figure 2]b, [Figure 2]c, [Figure 2]d, [Figure 2]e. Diagnosis of PHE was offered. Subsequently, multiple resection specimens of the various nodules over anterolateral, posteromedial regions, Achilles tendon, and tibial curettage revealed features of PHE. Postexcision, the patient was offered skin grafting over his left leg [Figure 3]a.
|Figure 2: Immunohistochemical results. (a) Tumor cells displaying pancytokeratin (AE1/AE3) positivity (DAB, ×400). (b) CD31 positivity (DAB, ×400). (c) Diffuse FLI1 positivity (DAB, ×400). (d) Retained INI/SMARCB1 expression (DAB, × 400). (e) Ki67 highlighting 20% tumor cell nuclei (DAB, ×400)|
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|Figure 3: (a) Clinical photograph showing a healed graft 4 months after excision of the leg lesions. (b) Multiple superficial nodular lesions over plantar aspect of fourth toe. (c) Cut surface of fourth toe disarticulated specimen showing multiple tumor lesions (asterix). (d) Microscopic examination revealing a distinct tumor nodule in the dermis, infiltrating the bone (arrowheads) (H and E, ×10). (e) Tumor cells in higher magnification (H and E, ×400)|
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Three months later, the lesion over his fourth toe progressed along with multiple nodules over the dorsal and ventral surfaces of his left foot for which he underwent fourth toe amputation and wide resections that revealed PHE. Occasional mitotic figures were identified [Figure 3]b, [Figure 3]c, [Figure 3]d, [Figure 3]e. The patient is free of disease for 16 months after his initial presentation.
| Discussion|| |
PHE is a recently described soft tissue tumor that was previously designated as an epithelioid sarcoma-like hemangioendothelioma., Hornick and Fletcher  observed this tumor most frequently occurring in males, presenting with either painless or painful nodules, commonly as a multifocal disease (66% cases), in their lower limbs, within muscles, dermis, and subcutaneous tissues, as noted in the present case.
Besides multifocal soft tissue lesions, our patient also harbored a bony lesion that was identified as another highly 18 F-FDG PET avid lesion. HornickandFletcher  observed bony involvement in 10/50 cases (20%). Subsequently, various authors, who documented bone involvement in PHE, observed that almost all such cases were characterized by multifocal lesions [Table 1].,,,,,, Amary et al. observed 2 of 3 cases of PHE involving bones with FDG-PET avid lesions. In a recently documented case of an intraosseous PHE, the patient presented with numerous 18 F-FDG-PET avid lytic lesions in his humerus that were presumed to be metastatic or myeloma. Another intraosseous PHE with pulmonary metastasis was recently documented. The present case constitutes as the 18th case of PHE involving the bone and the first documented case of PHE from our continent.
|Table 1: Literature review of cases of pseudomyogenic hemangioendothelioma involving bone|
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The value of identifying this tumor is that clinically, it appears as a high-grade sarcoma, in view of its multifocality; high FDG-PET avidity and can histopathologically be misdiagnosed as a high-grade sarcoma, as noted in our case. In contrast to a high-grade sarcoma, most cases of PHE display an indolent behavior. Isolate lesions in such cases PHE can be underdiagnosed as a dermatofibroma.
Various differential diagnoses include an epithelioid sarcoma, an epithelioid angiosarcoma, a rhabdomyosarcoma, and an epithelioid leiomyosarcoma. An epithelioid sarcoma is characterized by nodular aggregates of epithelioid cells, rather than only plump spindly cells. An epithelioid angiosarcoma invariably shows areas of hemorrhage with lumens, features that were lacking in all the tumor lesions in the present case. In view of plump spindle cells, probably diagnosis of spindle cell rhabdomyosarcoma was considered at the referring laboratory. Immunohistochemical results, including lack of desmin, myogenin, and myoD1 expression, objectively ruled out a rhabdomyosarcoma. In view of AE1/AE3 immunoexpression, an epithelioid sarcoma was a close differential diagnosis. Aforementioned histopathological features with retained INI1/SMARCB1 expression ruled out this tumor. Despite SMA positivity, rather banal appearing nuclei, infrequent mitoses and lack of necrosis helped in ruling out a leiomyosarcoma.
Exact diagnosis has therapeutic implications. While case of multifocal PHE is treated with surgical resection, a multifocal spindle cell rhabdomyosarcoma is treated with IRS IV chemotherapy and radical resection. Epithelioid sarcoma and epithelioid angiosarcoma have propensity for lymph node metastasis; therefore, in case of multifocality would be treated with adjuvant radio and or chemotherapy and radical resections. Lately, SERPINE1-FOSB fusion gene resulting in transcriptional upregulation of FOSB has been identified in PHEs.
To summarize, PHE should be suspected in young adults with multifocal subcutaneous lesions that are highly FDG-PET avid and display plump spindly cells on histopathology. IHC markers are helpful in differentiating PHE from a spindle cell rhabdomyosarcoma as either of these tumors have different treatment and prognostic implications.
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Conflicts of interest
There are no conflicts of interest.
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Dr. Bharat Rekhi
Department of Pathology, 8th Floor, Annex Building, Tata Memorial Hospital, Dr. E.B. Road, Parel, Mumbai - 400 012, Maharashtra
Source of Support: None, Conflict of Interest: None
[Figure 1], [Figure 2], [Figure 3]