Primary Epithelioid Sarcoma Manifesting as a Fungating Scalp Mass - Imaging Features and Treatment Options. A Case Report and Literature Review

Primary epithelioid sarcoma is an extremely rare malignancy of the scalp. To date, less than a dozen such cases have been reported in the literature. The diagnosis often is a challenge to both radiologists and clinicians. This is largely attributed to the lack of literature on the imaging features of scalp epithelioid sarcoma. In this report, we highlight the role of multimodality imaging in the diagnosis of primary scalp epithelioid sarcoma and review the epidemiology, imaging, treatment options, and prognosis of these malignant scalp tumors. Displaying a multilobulated morphology, heterogeneous enhancement, and restricted diffusion on MRI, these tumors typically show central degeneration with hemorrhage, necrosis, and calcification. Wide surgical resection and adjuvant radiotherapy are the mainstays of treatment for localized scalp tumors. Nevertheless, the prognosis of patients with distant metastases at diagnosis is extremely poor compared to those with local or regional diseases.

Infantile Extracranial Rhabdoid Tumor of the Scalp

Extracranial rhabdoid tumor is a rare tumor that can originate in multiple organs, and it is most commonly seen in the kidneys. This tumor has a grave prognosis. We report to the best of our knowledge the first case of infantile scalp extracranial rhabdoid tumor in a 6-month-old male baby who presented with a right parietal scalp mass since the age of 1 month. This mass was initially diagnosed as scalp hemangioma based on clinical and imaging findings. However, this mass was growing fast which necessitated excision. Pathologic examination after excision showed a malignant tumor composed of sheets of rhabdoid cells. Immunohistochemically, this tumor tested positive for vimentin, CD 99, glypican-3, synaptopysin, WT-1, CK, and EMA. INI-1 immunostain was lost in the tumor cells. Subsequently, this tumor was pathologically diagnosed as extracranial scalp rhabdoid tumor. After tumor excision, the patient was referred to pediatric oncology to receive chemotherapy. Experience with scalp extracranial rhabdoid tumors is limited. However, this tumor in other organs carries a grave prognosis. Although scalp extracranial rhabdoid tumor is an extremely rare tumor, it should be kept in mind in the differential diagnosis of infantile scalp masses given the need of combined surgical and chemotherapeutic treatment.

Scalp mass: an atypical presentation of multiple myeloma

A 64-year-old male with no history of trauma presented to the general surgery clinic with a 6-month history of an asymptomatic left parietal scalp mass. The differential included benign etiologies such as lipoma or sebaceous cyst. At surgery, a hemorrhagic soft tissue mass with underlying defect in the parietal calvarium was noted. The initial attempt at resection was abandoned and neurosurgical consultation was requested. Magnetic resonance imaging demonstrated an enhancing scalp mass with a lytic lesion of the parietal calvarium with no intradural extension. Craniectomy with mass resection and mesh cranioplasty were performed. Pathology confirmed plasma cell neoplasm; serum protein electrophoresis and lytic skull lesions confirmed multiple myeloma. This rare presentation of multiple myeloma serves as a call for providers to maintain a broad differential when evaluating a seemingly benign mass, consider rare etiologies when appropriate and maintain vigilance for abnormal findings during any procedure.

Extracranial Meningioma in the Scalp with Concurrent Steatocystoma

This report documents a rare case of an extracranial meningioma on the posterior scalp without apparent dural connection. Additionally, a sebaceous steatocystoma of the anterior scalp presented alongside the meningioma. A steatocystoma localized to the scalp is also remarkably rare. To our knowledge, this is the first report documenting both an extracranial meningioma and a steatocystoma presenting concurrently on the scalp. A male patient in his thirties presented with a mass lesion on the scalp. A CT scan revealed one posterior scalp mass with no intracranial abnormalities. Post excision histologic examination confirmed an extracranial meningioma (meningothelial variant, WHO Grade I). A second anterior scalp mass, not revealed by CT scan, was discovered during surgery. It was excised and diagnosed as a steatocystoma. Meningiomas predominantly occur intracranially but, in some instances, may present as a standalone extracranial tumor without intracranial abnormalities. Because extracranial meningioma is uncommon, it may be overlooked during clinical diagnosis of scalp masses. We recommend that this neoplasm be routinely considered in the differential diagnosis of extracranial tumors. The discovery of another rare tumor—a steatocystoma located in immediate proximity on the scalp—is further remarkable. We briefly review relevant case reports and etiologies and consider a potential relationship between the two neoplasms. However, it remains more likely that the concurrence of these tumors in our patient was simply coincidental.