Variety Of Sarcomas Research Articles

The last illness of I.S. Turgenev

The article discusses the causes and course of the last illness of I.S. Turgenev. The writer was consulted by many famous French and Russian doctors who made various diagnoses and used various methods of treatment. The primary disease that caused Turgenev's death is myxosarcoma (one of the sarcoma variants), involving soft tissues and thoracic vertebrae. The article presents data and discusses alternative diagnostic versions about the nature of the disease and the causes of death of the great Russian writer.

Rhabdoid Differentiation in Wilms Tumor

ABSTRACT Wilms tumor (WT) is a relatively common pediatric tumor. Depending on the stage of disease, treatment includes surgery, chemotherapy, and radiotherapy. Chemotherapy and radiotherapy can induce differentiation of tumor cells to rhabdoid morphology that can masquerade as rhabdoid tumor of the kidney. We report a rare case of WT with rhabdoid differentiation subsequent to treatment with neoadjuvant chemotherapy. Rhabdoid tumor of the kidney was initially considered a sarcomatous variant of WT, however was later classified separately due to distinct behavior. This makes it challenging to differentiate from WT with rhabdoid differentiation which is important as that would also affect the aggressiveness of treatment and prognosis.

Molecularly Confirmed Pseudomyogenic Hemangioendothelioma with Unusual EGFL7::FOSB Fusion in the Head and Neck Region of an Older Patient

Pseudomyogenic hemangioendothelioma (PMHE), a rare vascular neoplasm, was first described in 1992 asa fibroma-like variant of epithelioid sarcoma, and would be termed as epithelioid sarcoma-like hemangioendothelioma a decade later due to its significant histologic overlap with epithelioid sarcoma and diffuse cytokeratin expression. PHME is currently defined as a distinct, potentially intermediate malignant, rarely metastasizing neoplasm with vascular/endothelial differentiation. It is characterized by young age (typically less than 40 years old), extremity location (approximately ~80%), and t(7:19) SERPINE1::FOSB fusion as the most common molecular alteration. Herein, we report a case of a 59-year-old male presenting with multifocal lesions, including in the right temporalis muscle, right frontoparietal calvarium, right pterygoid muscles, and right mandibular condyle. Histologic examination of the right temporal lesion revealed a multinodular biphasic lesion composed of sheets and fascicles of elongated spindle and epithelioid cells infiltrating into the adjacent skeletal muscle. Admixed abundant neutrophilic infiltration is noted; however, areas of necrosis, increased mitosis, nuclear atypia, or rhabdomyoblast-like cells are absent. Immunohistochemical (IHC) staining showed that the tumor cells were diffusely and strongly positive for FOSB, pan-cytokeratin (AE1/AE3), CD31, and ERG. Molecular testing demonstrated a t(9:19) EGFL7::FOSB fusion mRNA. This constellation of morphological, IHC and molecular findings was consistent with a diagnosis of PMHE. This is the first reported case of multifocal PMHE with EGFL7::FOSB fusion in the head and neck area of a patient aged more than 50 years old. Since the differential diagnoses for PMHE includes high-grade malignancies with aggressive clinical behavior, coupled with the rare reports of PMHE in the head and neck region, awareness of this tumor in the head and neck region will avoid the misdiagnosis and overtreatment of this entity.

A case of rapidly progressing sarcomatous intrahepatic cholangiocarcinoma with suddenly appearing lymph node metastasis

BackgroundThe sarcomatous variant of carcinoma is relatively rare in intrahepatic cholangiocarcinoma (ICC). Sarcomatous ICC (SICC) is associated with a poorer prognosis compared with ICC. SICC is rarely diagnosed before surgery due to non-descriptive findings; it progresses rapidly, resulting in miserable prognosis. Here, we report a case of rapidly progressing SICC that showed a clinically significant tumor growth rate.Case presentationA 77-year-old woman who had undergone ileocecal resection for cecal cancer 5 years previously was found to have elevated levels of the tumor marker carbohydrate antigen 19-9. Although an abdominal computed tomography (CT) scan did not detect any liver mass lesions until 3 months before this serum examination, the subsequent CT scan revealed a hypodensity 20 mm mass lesion in the right anterior section. Contrast-enhanced CT and magnetic resonance imaging revealed peripheral enhancement in the arterial-to-equilibrium phase. Fluorodeoxyglucose positron emission tomography revealed uptake in the lesion. None of the imaging modalities showed lymph node swelling or distant metastases. She underwent hepatectomy under the diagnosis of ICC or an atypical metastasis from previous cecal cancer. Although preoperative images showed no suspicious lymph node metastasis 3 weeks prior, the hilar lymph node swelled 3 cm and contained adenocarcinoma. Consequently, the patient underwent right anterior sectionectomy and lymph node dissection of the hepatoduodenal ligament. Histopathological examination revealed that the liver tumor was a poorly differentiated adenocarcinoma with sarcomatous pattern. While the patient received adjuvant gemcitabine and S-1 therapy, lymph node metastasis appeared in the mediastinum 13 months after the surgery. She received gemcitabine + cisplatin + S-1 therapy but died 20 months after surgery.ConclusionSICC and lymph node metastasis clinically appeared within 3 months and 3 weeks, respectively. Suspected ICC that rapidly progresses should be considered SICC and treated with early resection. SICC is often missed in clinical diagnosis and has a poor prognosis, even after curative resection. While an alternative strategy involving preoperative biopsy and neoadjuvant therapy may be beneficial, it should be approached with discretion due to the potential risks of tumor progression and peritoneal dissemination.

PAEDIATRIC-06 PEDIATRIC RECURRENT PRIMARY OCCIPITAL SYNOVIAL SARCOMA: A CASE REPORT

Abstract BACKGROUND Synovial sarcoma is one of the malignant soft tissue sarcomas with an unknown histological origin. It has a unique t(X;18) (p11.2; q11.2) chromosomal translocation, resulting in the SYT-SSX fusion protein. The intracranial occurrence is mainly metastatic, and primary intracranial synovial sarcoma is extremely rare, with few case reports and case series in the literature.Surgical resection of the tumor followed by adjuvant radiotherapy and chemotherapy, regardless of the extent of tumor resection, has been shown to have a significant benefit. CASE PRESENTATION Here we report the case of an eleven-year-old male patient who presented with a four-month history of swelling at the occipital area and intermittent headache. Imaging showed a destructive skull vault lesion with infiltration of the ipsilateral cerebellum. A subtotal resection of the tumor was achieved, and histopathology examination revealed a biphasic variant of synovial sarcoma. The patient disappeared from follow-up without receiving adjuvant radiotherapy and presented two years later with a swelling at the previous surgical site. After imaging was done, a recurrence was diagnosed, and he was reoperated with near total excision. CONCLUSION Primary intracranial synovial sarcoma is an extremely rare malignant tumor. Surgical resection with adjuvant radiation should be the standard of care to prevent recurrence. In low-income countries, patients disappear from follow-up, making post-operative management difficult. Furthermore, radiation services should be made widely available to address issues with compliance.

Biphasic synovial sarcoma with myoepithelial features: a distinctive variant with a predilection for the foot.

Synovial sarcoma (SS) is a tumor known for its classic monophasic spindle cell or biphasic morphology. However, it exhibits a wide range of histologic variations, leading to diagnostic challenges. Here, we present four cases of molecularly confirmed, biphasic SS originating in the feet and displaying myoepithelial differentiation. The patients were two men and two women with an age range from 19 to 71 years (mean, 45 years). Each tumor showed foci with conventional spindle cell morphology. The epithelial components included areas with nests and cords of epithelioid cells set within a hyalinized and sclerotic stroma. The cytoplasm was clear to pale and eosinophilic. The nuclei were ovoid-round with fine chromatin and small to inconspicuous nucleoli. Mitotic figures were present (2-13 per 10 high-power fields; mean, 6.5). Immunohistochemical studies showed variable staining of the myoepithelial-like regions for low molecular weight keratins, EMA, p63, and S100 protein. Molecular studies confirmed the presence of SS18::SSX1/2 fusion in all four tumors. These cases highlight an unusual variant of synovial sarcoma with an apparent predilection for the distal lower extremity and suggest that differentiation of biphasic synovial sarcoma may be impacted by the anatomic site. Awareness of this variant is important to avoid misclassification and potential treatment and prognostic implications.

DNA Methylation Profiling Distinguishes Adamantinoma-Like Ewing Sarcoma From Conventional Ewing Sarcoma

Adamantinoma-like Ewing sarcoma (ALES) has traditionally been considered a variant of Ewing sarcoma because it generally harbors EWSR1::FLI1 fusions despite showing diffuse positivity for keratins and p40. However, it has become increasingly recognized that different tumors can have identical translocations, including shared fusions between carcinomas and sarcomas, raising questions as to whether ALES might represent a separate entity. Using methylation profiling, we further explored the relationship between Ewing sarcoma and ALES. The archives of multiple institutions were searched for candidate cases of ALES. DNA methylation profiling was performed and results were compared to corresponding data from conventional Ewing sarcoma. Twelve cases of ALES (5 previously reported) were identified in 10 men and 2 women (aged 20-72 years; median age, 41.5 years). Cases included tumors arising in the parotid gland (3), sinonasal cavity (2), submandibular gland (2), thyroid gland (1), neck (1), gingiva (1), hypopharynx (1), and mandible (1). Histologic review consistently showed sheets and nests of basaloid cells within a fibromyxoid or hyalinized stroma. All tumors were positive for at least 1 keratin and CD99 expression, whereas all 10 cases tested were positive for p63 or p40; S100 protein expression was noted in 2 cases. Cases harbored either EWSR1::FLI1 fusions (n = 6), FUS::FLI1 fusions (n = 1), and/or EWSR1 rearrangements (n = 6). Methylation profiling was successful in 11/12 cases evaluated. Unsupervised clustering and dimensionality reduction (Uniform Manifold Approximation and Projection) of DNA methylation data revealed a distinct methylation cluster for all 11 cases, including the tumor with the FUS::FLI1 fusion, which clearly segregated them from the conventional Ewing sarcoma. Follow-up (n = 11, 1-154 months) revealed that 4 patients experienced recurrence and 6 developed metastatic disease. ALES demonstrates a distinct methylation signature from conventional Ewing sarcoma. This finding adds to the distinctive immunoprofile of ALES, suggesting that these 2 tumors should be considered distinct entities rather than histologic extremes of the same disease.

Adamantinoma-like Ewing Sarcoma (ALES) May Harbor FUS Rearrangements : A Potential Diagnostic Pitfall.

Adamantinoma-like Ewing sarcoma (ALES) is a rare malignancy currently considered a variant of Ewing sarcoma with most known cases harboring EWSR1 rearrangements. Herein we present a series of 6 cases of EWSR1 -negative ALES. The tumors arose in the sinonasal tract (n=3), major salivary glands (submandibular gland=1; parotid=1), and anterior mediastinum (n=1) in patients ranging from 25 to 79 years of age. Most tumors were basaloid in appearance, growing in large nests separated by interlobular fibrosis without overt squamous pearls. However, 1 case closely resembled a well-differentiated neuroendocrine tumor with uniformly round nuclei, eosinophilic cytoplasm, and trabecular architecture. All cases were diffusely positive for pan-cytokeratin, p40 or p63, and CD99. A subset of cases showed diffuse reactivity for synaptophysin, including 1 sinonasal tumor which also demonstrated sustentacular S100 protein expression. Molecular testing showed FUS rearrangements in all cases. Gene partners included known ETS family members FEV (n=2) and FLI1 (n=1). Our results expand the molecular diagnostic considerations for ALES to include FUS rearrangements. We also show that ALES may harbor FUS :: FLI1 fusion, which has not been previously reported in the Ewing family of tumors. Furthermore, ALES may show unusual histologic and immunophenotypic features that can overlap with olfactory carcinoma including S100-positive sustentacular cells. ALES should be considered in the diagnostic differential of small round cell tumors and tumors with neuroendocrine differentiation with immunohistochemical workup to include p40 and CD99/NKX2.2.

CIC-rearranged sarcoma: a clinicopathological analysis of four cases

Objective: To investigate the clinicopathological features and differential diagnosis of CIC-rearranged sarcoma (CRS). Methods: Five CRSs of 4 patients (2 biopsies of pelvic cavity and lung metastasis from case 4) diagnosed in the First Affiliated Hospital of Nanjing Medical University were enrolled from 2019 to 2021. All cases were evaluated by clinical presentation, H&E, immunohistochemical staining and molecular analysis and the related literature was reviewed. Results: There were one male and three females, the age at diagnosis ranged from 18 to 58 (mean 42.5) years. Three cases were from the deep soft tissues of the trunk and one case from the skin of foot. Grossly, the tumor size ranged from 1 to 16 cm. Microscopically, the tumor was arranged in nodules or solid sheets. The tumor cells were typically round or ovoid, with occasional spindled or epithelioid morphology. The nuclei were round to ovoid with vesicular chromatin and prominent nucleoli. Mitotic figures were brisk (>10/10 HPF). Rhabdoid cells were seen in four of five cases. Myxoid change and hemorrhage were observed in all samples and two cases showed geographic necrosis. Immunohistochemically, CD99 was variably positive in all samples, while WT1 and TLE-1 were positive in four of five samples. Molecular analysis showed CIC-rearrangements in all cases. Two patients succumbed within 3 months. One had mediastinal metastasis 9 months after surgery. One underwent adjuvant chemotherapy and remained tumor-free 10 months after diagnosis. Conclusions: CIC-rearranged sarcoma is uncommon and shows aggressive clinical course with dismal prognosis. The morphological and immunohistochemical characteristics can largely overlap with a variety of sarcomas; hence, knowledge of this entity is vital to avoid potential diagnostic pitfalls. Definitive diagnosis requires molecular confirmation of CIC-gene rearrangement.

Primary retroperitoneal squamous cell carcinoma: a literature review.

Retroperitoneal squamous cell carcinoma is an extremely rare histological variant of retroperitoneal tumors. The exact etiology and origin of the same is still unknown. To date, only a few case reports have been published in the literature. Due to rarity, standard treatment protocol is not available. The article aims to review the literature and treatment options available for this uncommon entity, based on available data. We searched the databases like PubMed, PubMed Central, Scopus, and Google Scholar with the keywords "Squamous cell carcinoma" and "retroperitoneal tumors". Peer-reviewed and recent articles were screened. Seven relevant articles comprising 14 cases were found. Due to the small number of reports, tabulation of treatment details and outcome was done. Like the sarcoma variant, these tumors also present with a large mass in the abdomen and abdominal discomfort. Association with human papillomavirus appears to be the most common factor that gives rise to squamous histology. Retroperitoneal SCC is an uncommonly diagnosed entity. Although no specific treatment guidelines exist for this uncommon malignancy; surgery followed by adjuvant or definitive radiotherapy with concurrent chemotherapy (in inoperable cases) seems a feasible option. Multicentre trials should be conducted for establishing definitive treatment strategies for this ailment.

No More "Cavernous Hemangioma," Please.

To The Editor: Recently, Haller et al published “A case of a rare histologic variant: Cavernous hemangioma-like Kaposi sarcoma.”1 We want to congratulate the authors for such a remarkable diagnosis of a rare variant. This variant of Kaposi sarcoma refers to the dilated vascular spaces that are evidenced in the tumor, mimicking what was known in the 1980s as “cavernous hemangioma.”2 The latter is a misnomer: What was called a “cavernous hemangioma” is in fact a vascular malformation.3–5 In the correct diagnostic and therapeutic approach to vascular anomalies, proper identification as either vascular malformations or tumors has been crucial. For that, a long path has been traveled in the past decades, up to the point that erroneous terms, such as “cavernous hemangioma,” have been present in relevant texts until recently. The term was still included in the third Edition of the WHO Book of Skin Tumors.6 In the fourth Edition,7 although “cavernous hemangioma” is not described among the list of vascular tumors, it is still included as such in the differential diagnosis of “cavernous hemangioma-like Kaposi sarcoma” (authors' Table 5.02).8 In the fifth Edition of the WHO book for Soft Tissue and Bone tumors,9 the “cavernous variant” of Kaposi sarcoma is not mentioned and “cavernous hemangioma” is not included among vascular tumors. In addition, cavernous hemangioma is not included in the fifth edition of the WHO Book of Pediatric Tumors,10 in which simple vascular malformations (other than arteriovenous or verrucous venous) are included for the first time in the WHO tumors' series. All this indicates the progress made in comprehension of vascular anomalies that has been the result of the work and arguments made by several academic groups. This is why terms such as “cavernous hemangioma” should be avoided, even if, as in the current case, it is just mentioned as a variant of another tumor (Kaposi sarcoma). Despite this KS variant was mentioned as “cavernous hemangioma-like” in articles published in the 2010s,11,12 future articles should try to amend this and correct the misnomer for the good of future generations. The alternative term of “venous malformation-like Kaposi sarcoma” is not only adequate and appropriate but also does not require a great conceptual effort to be implemented.

An Unusual Endometrial Stromal Neoplasm With JAZF1-BCORL1 Rearrangement.

Endometrial stromal tumors represent the second most common category of uterine mesenchymal tumors. Several different histologic variants and underlying genetic alterations have been recognized, one such being a group associated with BCORL1 rearrangements. They are usually high-grade endometrial stromal sarcomas, often associated with prominent myxoid background and aggressive behavior. Here, we report an unusual endometrial stromal neoplasm with JAZF1-BCORL1 rearrangement and briefly review the literature. The neoplasm formed a well-circumscribed uterine mass in a 50-yr-old woman and had an unusual morphologic appearance that did not warrant a high-grade categorization. It was characterized by a predominant population of epithelioid cells with clear to focally eosinophilic cytoplasm growing in interanastomosing cords and trabeculae set in a hyalinized stroma as well as nested and fascicular growths imparting focal resemblance to a uterine tumor resembling ovarian sex-cord tumor, PEComa, and a smooth muscle neoplasm. A minor storiform growth of spindle cells reminiscent of the fibroblastic variant of low-grade endometrial stromal sarcoma was also noted but conventional areas of low-grade endometrial stromal neoplasm were not identified. This case expands the spectrum of morphologic features seen in endometrial stromal tumors, especially when associated with a BCORL1 fusion and highlights the utility of immunohistochemical and molecular techniques in the diagnosis of these tumors, not all of which are high grade.

Dermatofibrosarcoma protuberans challenges: a case series and review of the literature

BackgroundDermatofibrosarcoma protuberans (DFSP) is a rare variant of skin sarcoma which is characterized by proliferation of spindle cells in a storiform pattern. Although it is mostly benign in its primary stages, it can cause a high burden of morbidity unless it is thoroughly excised.Case presentationHere, we review six cases of DFSP which were characterized by skin lesions in various parts of the body. Patients were from 26 to 51 years old; four were Asian men and two were Asian women. Wide surgical excision was performed for all these patients and no extra treatment was considered. Samples were studied by hematoxylin and eosin (H&E) staining and immunohistochemical (IHC) tests. Only one of our patients experienced recurrence after the initial surgery.ConclusionDetermining the best surgical method is still a dilemma in the treatment of DFSP lesions. There are numerous studies to prove the efficacy of various surgical interventions. Although DFSP is not commonly known as a malignant skin lesion, delay in treatment will have a catastrophic impact on patients’ lives. Thus, applying an in-time surgical method (wide local excision in our cases) in treating DFSP is crucial in preventing recurrence as well as decreasing the morbidity burden of DFSP.

A Rare Case of Primary Spindle Cell Synovial Sarcoma of Scalp

Abstract Synovial sarcoma is a variant of soft-tissue sarcoma, but has a very aggressive course. It is very rare overall, constituting only 5%–10% of all soft-tissue sarcomas. Head and neck constitutes 3%–5% of cases. It is more common in males in the 15–40 years age group. Hence, histopathological confirmation is required for diagnosis along with radiological investigations like magnetic resonance imaging. If histopathology/immunohistochemistry also cannot give a definitive diagnosis, chromosomal translocation t(x; 18) (p11.2–q11.2) assay is required as it is present in more than 90% of cases. Rarity of cases leads to the absence of proper treatment guidelines. Here, we are reporting a case of a large primary spindle cell synovial sarcoma of the scalp in a 57-year-old female, developed just over a month, pushing brain parenchyma, describing her treatment by volumetric modulated arc therapy (VMAT) radiotherapy to spare surrounding critical organs, particularly brain and eyes.

Trends and morphologic variants of Kaposi Sarcoma as seen in Nnewi, Anambra State, Nigeria

Kaposi sarcoma (KS) is a human herpes virus type 8 (HHV-8) driven neoplasm with varying morphologic features and attendant diagnostic dilemma. This study presents the trend of KS in our environment and the different morphologic variants, with a view to arousing awareness and reducing missed and delayed diagnosis. KS accounted for 18.34% and 59.66% of vascular neoplasms and malignant vascular neoplasms, respectively with most KS occurring in the background of human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS). The frequency peaked in 2013 and began to decline with a fairly even sex distribution. There are diverse variants of KS that can pose diagnostic challenges. Hence, there is need for this awareness to enhance prompt and accurate diagnosis.

Trends and morphologic variants of Kaposi Sarcoma as seen in Nnewi, Anambra State, Nigeria

Trends and morphologic variants of Kaposi Sarcoma as seen in Nnewi, Anambra State, Nigeria

CASE REPORT OF AN EPITHELIOID VARIANT OF KAPOSI SARCOMA: A RARE MIMIC OF ANGIOSARCOMA

Cutaneous Kaposi sarcoma (KS) is a vascular neoplasm with a broad spectrumclinicopathology. An epithelioid morphology, a rare recent variant of KS, with many variants of KS that may mimic other vascular neoplasms poses a diagnostic challenge. We report on a 75-year-old Saudi man HIV- negative who had been diagnosed with classical KS on the right foot 8 years before the present episode. Histopathological findings of the new lesion included areas showing epithelioid cells with moderate pleomorphism, growing in solid sheets. The epithelioid cells show nuclear enlargement and hyperchromasia mimicking angiosarcoma. Immunohistochemistry shows a strong diffuse nuclear staining pattern for HHV-8 latent nuclear antigen-1 (LNA-1) in the epithelioid as well as the classical spindle cells. A diagnosis of epithelioid Kaposi sarcoma is made, which should be included within the known histological variants of KS. Prior to this case, the epithelioid variant of Kaposi sarcoma has been reported only three times in the literature. Since this variant shares similar clinical and histological features with angiosarcoma, integration of clinical findings and context, histopathologic features and immunohistochemical results is critical in obtaining the correct diagnosis and treatment.

A multicenter evaluation of treatment patterns and outcomes for Adamantinoma-like Ewing sarcoma.

e23500 Background: Sarcomas are a rare and heterogenous group of malignancies comprised of > 150 histologic subtypes. Adamantinoma-like Ewing sarcoma (ALES) is a rare, small round blue cell tumor that represents a variant of Ewing sarcoma (EWS). First described 20 years ago, ALES harbors a EWS subset defining EWS-related translocation; however, ALES has a complex epithelial differentiation component defining it as a distinct clinical entity. Most ALES cases arise in the head and neck, but it has also been reported in the extremities and thorax. Given the rarity of ALES, there is a paucity of literature to guide treatment and describe outcomes. Methods: We performed a retrospective review (January 1, 2010-January 1, 2022) at two sarcoma centers in the United States and identified 4 cases of ALES. Tumor and patient characteristics were described, and patient outcomes were assessed. Results: Four patients were identified. 3 (75%) were male. Median age at diagnosis was 37 years (range 23-57). Primary site of ALES was head and neck (50%) and thorax (50%). Median tumor size was 4 cm (2.7-5.5 cm). All patients underwent resection of their primary tumor, and two (50%)received adjuvant radiation therapy. All pts received/are receiving adjuvant chemotherapy. 75% of patients were treated with Vincristine, Doxorubicin, and Cyclophosphane (VDC) alternating with Ifosfamide & Etoposide (IE) for 12-14 cycles. One patient received 4 cycles of adjuvant carboplatin and etoposide and radiation after an initial diagnosis of basaloid carcinoma but recurred 47 months later and diagnosed at ALES at that time. That patient underwent re-resection followed by adjuvant chemotherapy with Vincristine, Doxorubicin, and Ifosfamide (VAI). Median follow-up from initial diagnosis was 25 months (3-39 months). All patients are alive with no evidence of disease. Conclusions: Similar to treatment of EWS, a multidisciplinary strategy is paramount. VDC/IE is a reasonable treatment strategy. Further multicenter collaboration is essential to define clinical characterization of this rare sarcoma subtype and to guide treatment particularly in the relapsed or refractory setting.[Table: see text]

Imaging of Complications of Chemoradiation.

Chemoradiation for head and neck cancer is associated with a variety of early and late complications. Toxicities may affect the aero-digestive tract (mucositis, salivary gland injury), regional osseous and cartilaginous structures (osteoradionecrosis (ORN) and chondronecrosis), vasculature (progressive radiation vasculopathy and carotid blow out syndromes), and neural structures (optic neuritis, myelitis, and brain injury). These may be difficult to distinguish from tumor recurrence on imaging, and may necessitate the use of advanced MRI and molecular imaging techniques to reach the correct diagnosis. Secondary radiation-induced malignancies include thyroid cancer and a variety of sarcomas that may manifest several years after treatment. Checkpoint inhibitors can cause a variety of adverse immune events, including autoimmune hypophysitis and encephalitis.

25671 Nonepidemic variant of Kaposi sarcoma in an immunocompetent HIV-negative male

A 30-year-old man with no significant past medical history presented for evaluation of a growth on his nose that appeared 3 months prior. He reported having several female sexual partners in the past with whom he did not consistently use condoms. HIV testing 6 months prior was negative. Physical examination revealed a solitary 7-mm pink to red papule on the nasal dorsum. No other skin or mucosal lesions were identified. There was no cervical, axillary, or inguinal lymphadenopathy. Laboratory workup including CBC, CMP, serum immunoglobulins, and SPEP were unremarkable. HIV 1 and 2, and HTLV-1 and 2 were negative. Shave biopsy revealed a dermal spindle cell proliferation arranged in short intersecting fascicles admixed with plasma cells and occasional mitotic figures. Immunohistochemical studies showed spindled cells stained with CD34. CD31 and HHV8 staining were also positive. Kaposi sarcoma (KS) is a rare angioproliferative disorder associated with infection with human herpes virus 8 (HHV-8). There are 4 recognized epidemiologic forms: classic, endemic, epidemic, and iatrogenic. A recently described fifth type, nonepidemic KS, occurs in a rare subset of individuals who do not fit other classifications. This includes HIV-negative individuals without detectable cellular or humoral immunodeficiency. This subset has been described as clinically similar to classic KS with limited disease, but occurring in younger men. Although nonepidemic KS is generally indolent with a good prognosis, secondary lymphoproliferative disorders, including Castleman disease and lymphoma, have been reported. This report highlights a case of nonepidemic KS and discusses important relevant diagnostic and management considerations.