A Tale of Two Tumors: A Collision Tumor of Atypical Fibroxanthoma and Basal Cell Carcinoma.

ABSTRACT: A collision tumor is an infrequent phenomenon characterized by the presence of 2 histologically distinct tumor types (either benign or malignant) occurring within the same specific anatomical site. We describe a rare case of co-occurrence of basal cell carcinoma and atypical fibroxanthoma presenting as a single lesion on the scalp in a 76-year-old man. The lesion was clinically suspicious for basal cell carcinoma and biopsied. Histologic examination showed 2 distinct tumors, one with basaloid cells and the other one with pleomorphic spindle cells colliding and growing together. Immunohistochemical stains were crucial in establishing the diagnosis. This presentation is exceedingly rare and requires additional evaluation for diagnosis.

Primary Pulmonary Myxoid Sarcoma and Thoracic Angiomatoid Fibrous Histiocytoma: Two Sides of the Same Coin?

Primary pulmonary myxoid sarcoma (PPMS) and thoracic angiomatoid fibrous histiocytoma (AFH) are rare neoplasms with EWSR1 fusions and overlapping morphology. Both tumor types often show epithelial membrane antigen expression, but AFH characteristically co-expresses desmin. We encountered a case of PPMS with the unexpected finding of patchy, strong anaplastic lymphoma kinase (ALK) (previously reported in AFH) and synaptophysin expression. We evaluated a cohort of PPMS and thoracic AFH with systematic morphologic comparison and surveyed for aberrant expression of ALK and synaptophysin. Medical records and slides were reviewed for 16 molecularly confirmed cases of PPMS (n=5) and thoracic AFH (n=11). Each case was scored for morphologic characteristics typical of PPMS and/or AFH. ALK, synaptophysin, chromogranin, desmin, and epithelial membrane antigen immunostains were performed on cases with available tissue. AFH and PPMS cases showed similar age at presentation and long-term tumor behavior. Almost all cases of PPMS and AFH had a fibrous pseudocapsule and lymphoid rim. All PPMS had myxoid stroma and reticular growth pattern, but these features were also present in a subset of AFH. Synaptophysin expression was present in 6 of 11 AFH and 1 of 5 PPMS; all tested cases were negative for chromogranin (n=15). One case of AFH and 1 case of PPMS showed focally strong coexpression of synaptophysin and ALK. AFH and PPMS show considerable clinicopathologic overlap. When supportive, the immunohistochemical findings described may aid in diagnosis before molecular confirmation. PPMS and AFH may be morphologic variants of the same clinicopathologic entity, which can show more immunophenotypic variability than previously reported.

Clinicopathological analysis of sclerosing angiomatoid nodular transformation in the spleen.

Background: Splenic sclerosing angiomatoid nodular transformation (SANT) is a rare benign nodular lesion in the red medulla of the spleen. In the past, SANT has not been consistently recognized as the name for this condition and was often misdiagnosed for other conditions. In recent years, SANT has been acknowledged by most scholars as multiple reports have been published. Aim: To assess the clinicopathological features of SANT to identify the histological characteristics of SANT to improve diagnosis and clinical treatment. Materials and Methods: We assessed 25 cases of SANT diagnosed at Zhongshan Hospital affiliated with Fudan University from September 2014 to October 2021, including 14 men and 11 women, aged 24-62 years old. Results: Fourteen cases were complicated with benign tumors of the liver, pancreas, kidney, uterus, and prostate. One case was complicated with renal clear cell carcinoma, and one was complicated with hepatocellular carcinoma. The gross neoplasm is multinodular and well defined. Histologically, angiomatoid nodules are composed of fattened, round, or irregular blood vessels, with or without red blood cells in the lumen, with unequal red blood cell extravasation, and fibrocytes around the nodules. The hemangiomatous nodules were positive for CD31 and CD34, while the vascular wall smooth muscle cells and fibrocytes around the nodules were positive for SMA. Conclusion: The diagnosis of SANT requires a combination of immunohistochemical and histological features, and early splenectomy is crucial for treatment.

168 Cases of aneurysmal dermatofibroma and 29 cases of hemosiderotic dermatofibroma: A clinicopathologic study.

OBJECTIVES: Aneurysmal dermatofibroma (ADF) and hemosiderotic dermatofibroma (HDF) are rare variants of dermatofibroma (DF) characterized by distinct histologic features. While HDF is traditionally considered a precursor to ADF, supporting evidence is limited, and the etiology remains unclear. A retrospective analysis of 2128 DF cases (2016-2019) was conducted to investigate the clinicopathologic characteristics of ADF, HDF, and other DFs. METHODS: Histopathologically diagnosed DF cases were examined for ADF and HDF. Univariate analyses were performed to compare clinicopathologic features. RESULTS: Among the cases, 168 (7.9%) were ADF and 29 (1.4%) were HDF. Aneurysmal dermatofibroma and HDF shared several common characteristics, including lower occurrence in females, larger size, and increased cellularity (all P < .0001). Notably, 29% of ADFs lacked hemosiderin deposition. Aneurysmal dermatofibroma primarily manifested on exposed areas (face and forearm, both P < .001). In contrast, 41% of HDFs occurred on the lower leg (P = .018), and all lower leg HDFs exhibited signs of venous stasis, distinguishing them from other HDFs (P < .0001). CONCLUSIONS: Our findings indicate a potential close relationship between ADF and HDF. Contrary to conventional beliefs, we also presented the possibility of ADF progressing into HDFs. Physical trauma may induce ADF, and HDFs may emerge from ADFs in conjunction with venous stasis in the lower extremities.

Recurrent and metastatic cellular cutaneous fibrous histiocytoma: A case report and literature review.

Cutaneous fibrous histiocytoma (FH) is considered a benign dermal tumor. The cellular variant is rare and poorly documented. Besides presenting a high risk of local recurrence, it has a low but serious metastatic potential. We present a case of metastatic cellular FH and also review the literature on this tumor, given its unusual metastatic development. A 47-year-old male patient presented with a lesion in the anterior surface of the right thigh, which has been present since adolescence but had grown during last year. Anatomopathological evaluation revealed a cellular FH, and the lesion was completely removed. Six months later, tumor recurrence with multiple compartment muscle involvement and pulmonary metastasis were detected. Both lesions were completely resected and after 3 years of follow-up, the patient is asymptomatic and free of the disease. We conclude that FH should be carefully sampled to detect variants with high local recurrence rates or with some metastatic risk such as the cellular one. We recommend wide surgical resection and a close follow-up including chest x-rays or thorax computed tomography (CT) in all cellular FH cases with local recurrence.

A study of collagen refractility in dermatofibroma and dermatofibrosarcoma protuberans using diffractive microscopy.

BACKGROUND: Diffractive microscopy creates contrast within samples that are otherwise uniform under bright light. This technique can highlight subtle differences in refractive indices within birefringent samples containing varying amounts of mature collagen. Dermatofibroma (DF) and dermatofibrosarcoma protuberans (DFSP) possess differences in their mature collagen content and, therefore, may be distinguishable using diffractive microscopy. METHODS: Two hundred forty-two DF and 85 DFSP hematoxylin-eosin (H&E)-stained specimens were analyzed using diffractive microscopy. Data regarding the distribution pattern and strength of refractility was recorded. RESULTS: DFSP was more frequently found to be focally, weakly, or non-refractile (82.9%; n = 68) under diffractive microscopy, while DF more often showed diffusely bright refractility (52.9%; n = 128). DFSP samples with diffuse refractility in portions of the lesion (17.1%; n = 14) also exhibited a unique checkerboard pattern distinct from that which was seen in DF samples. CONCLUSIONS: The absence of diffuse refractility was more closely associated with DFSP, as was the presence of a unique checkerboard diffraction pattern. Despite high sensitivity (Sn = 82.9%), absent refractility was not a specific test (Sp = 52.9%), with 47.1% (n = 114) of DF samples sharing this feature. The distinction between DF and DFSP is often diagnosed using H&E alone. In difficult cases, examination of collagen under diffractive microscopy may be useful in distinguishing DFSP from DF and provide an alternative cost-effective tool to immunohistochemical staining.

Epidermal inclusion cyst embedded in benign fibrous histiocytic lesion with prominent epithelioid morphology.

Benign fibrous histiocytoma also known as dermatofibroma is one of the common mesenchymal neoplasms. It commonly develops in young adult with female predominance and predilection for the extremities, particularly lower extremities. Implantation of epidermis in the dermis or subcutaneous tissues may lead to the formation of epidermal inclusion cyst, which is the most common type of epithelial cyst. Development of epidermal inclusion cyst within a benign fibrous histiocytoma is a rare occurrence. This is a unique case of two unrelated lesions.

Sclerosing angiomatoid nodular transformation (SANT) of the spleen: review of the literature / Nodular angiomatoide esclerosante transformación (SANT) de la bazo: revisión de la literatura

We present a sclerosing angiomatoid nodular transformation (SANT) case report in a 60 year-old-woman. SANT is an extremely rare benign disease of the spleen that it is radiologically similar to malignant tumors, and clinically difficult to differentiate from other splenic diseases. Splenectomy is both diagnostic and therapeutic in symptomatic cases. The analysis of the resected spleen is necessary to achieve the final diagnosis of SANT.(AU)

Connexin 43 in Dermatofibroma and Dermatofibrosarcoma Protuberans: Diagnostic, Pathogenic, and Therapeutic Implications.

ABSTRACT: Connexins play a crucial role in the formation of gap junctions that connect cells to each other, as well as cells to the surrounding environment. In recent years, connexin 43 has been extensively studied in various human tumors. In this study, we conducted an immunohistochemical analysis to evaluate the expression of connexin in 16 dermatofibromas (DFs) and 13 dermatofibrosarcoma protuberans (DFSP). Connexin was diffusely expressed in the cytoplasm of all DFs with moderate or strong intensity, whereas all DFSPs showed negative staining. In addition to its diagnostic implications, the loss of Cx43 may elucidate the invasive capacity of DFSP and offer a potential avenue for future therapeutic interventions.

Giant Sclerosing Hepatic Hemangioma Presenting as Bornman-Terblanche-Blumgart Syndrome: a Case Report and Review of the Literature.

Background: Hepatic hemangioma represents the most frequent benign tumor originating from the liver. When the tumor exceeds 10 cm, and in some studies 4 or 5 cm, it is considered giant, which accounts for 10% of all hemangiomas arising from the liver. Histologically, Sclerosing hepatic hemangioma, in particular, is an exceedingly rare subtype of hemangioma. Clinically Bornman-Terblanche-Blumgart syndrome is a very rare complication of hepatic hemangioma. Objective: The aim of this case presentation was to contribute to the literature by documenting a case of giant sclerosing hemangioma diagnosed in a 36-year-old female presenting with Bornman-Terblanche-Blumgart syndrome, along with a brief review of the literature. Case report: The current paper documents two rare clinical and histological features of hepatic hemangioma. Bornman-Terblanche-Blumgart syndrome is complicated a giant hepatic hemangioma found histologically to be sclerosing in nature. Knowledge about the uncommon complications of liver hemangioma permits the implementation of appropriate interventions in a timely manner and, in turn, can enhance the patient's quality of life and minimize rates of associated mortality.

Diagnostic value of high-frequency ultrasound (HFUS) in evaluation of subcutaneous lesions.

BACKGROUND: It is unknown whether high-frequency ultrasound (HFUS) can evaluate invisible subcutaneous lesions. We aimed to investigate the diagnostic value of HFUS in invisible subcutaneous lesions. METHOD: Patients with invisible subcutaneous lesions were prospectively recruited from two centres. Before undergoing biopsy or surgery, each lesion was independently evaluated by two clinicians. One provides a clinical diagnosis by only clinical examination and the other provides an integrated diagnosis by combining clinical examination and HFUS information. Diagnoses were classified as correct, wrong, and indeterminate. A total of 391 lesions from 355 patients were enrolled, including 225 epidermoid cysts, 77 lipomas, 25 pilomatrixomas, 21 haemangiomas, 19 dermatofibromas, 11 dermatofibrosarcoma protuberans (DFSP), 7 neurofibromas, and 6 leiomyomas. Using pathological results as the gold standard, diagnostic performance was compared. RESULTS: The number of correct diagnoses increased from 185 (47.3%) by clinical examination alone to 316 (80.8%) after the addition of HFUS (P < 0.05). Meanwhile, the indeterminate diagnosis rate decreased from 143 (36.6%) to 10 (2.6%). Using HFUS, the accuracy improved significantly for epidermoid cysts (59.6% vs. 86.7%), lipomas (50.6% vs. 94.8%), pilomatrixomas (0% vs. 48.0%), haemangiomas (23.8% vs. 57.1%), and DFSPs (0% vs. 81.8%) (all p < 0.05). However, HFUS did not significantly improve the diagnostic accuracy of dermatofibromas (15.8% vs. 21.1%, p > 0.999), neurofibromas (42.9% vs. 71.4%, p = 0.625), or leiomyomas (16.7% vs. 100%, p = 0.063). CONCLUSION: Combining HFUS and clinical examination can generally improve the diagnostic accuracy and decrease the indeterminacy of invisible subcutaneous lesions, especially epidermoid cysts, lipomas, pilomatrixomas, haemangiomas, and DFSPs. However, for some rare lesions, HFUS cannot provide useful information.

Sclerosing angiomatoid nodular transformation of the spleen in a child with anemia: a case report and review of the literature.

BACKGROUND: Sclerosing angiomatoid nodular transformation of the spleen is a relatively rare benign vascular lesion in both adult and pediatric age groups with unclear etiopathogenesis and variable clinical presentations. Many benign and also malignant splenic masses could mimic sclerosing angiomatoid nodular transformation, both clinically and radiologically. Herein, we report our experience with a case of sclerosing angiomatoid nodular transformation in a 3-year-old girl. CASE REPORT: A 3-year-old Iranian girl presented with abdominal pain, back pain, and constipation for 2 weeks. She was being followed up by a pediatrician due to her short stature and persistent anemia. Physical examination showed stable vital signs, short stature, pallor, and a puffy face. Laboratory evaluation showed normochromic normocytic anemia with a normal reticulocyte count, ferritin, and hemoglobin electrophoresis. Radiologic assessments revealed a hypoechoic lesion in the spleen with high vascularity, clinically suspected to be lymphoma. She was operated on, and after partial splenectomy, pathologic evaluation of the spleen showed a solitary, well-demarcated, and unencapsulated dark mass. Microscopic examination revealed micronodular appearance composed of irregular-shaped vascular spaces lined by plump endothelial cells and surrounded by concentric collagen fibers, features in keeping with sclerosing angiomatoid nodular transformation. The patient's anemia was resolved after surgery, and no clinical or radiologic deficits were noted during the 10-month follow-up visits. CONCLUSION: Although sclerosing angiomatoid nodular transformation is exceedingly rare in children, it should be considered a differential diagnosis in pediatric splenic neoplasms with concurrent hematologic manifestations, such as anemia.

Multiple sclerosing hemangiomas mimicking hepatocellular carcinoma: A case report.

Hepatocellular carcinoma is a prevalent malignant tumor affecting the liver, and surgical resection and liver transplantation are the primary treatment options for early-stage HCC patients. However, the presence of benign hepatic tumors with similar imaging characteristics to HCC poses challenges in diagnosing and treating the disease, often resulting in misdiagnosis and inappropriate treatment. This case report presents a 52-year-old female patient who exhibited space-occupying liver lesions on abdominal CT and MRI scans. Based on pathological sections from other hospitals, liver malignancy was highly suspected, and hepatocellular tumor was diagnosed preoperatively. But the tumor markers of the patient were all within the normal range. After evaluating the overall condition of the patient, we finally chose the diagnosis and treatment of dissection and partial hepatectomy. Surprisingly, the final diagnosis of postoperative pathology was sclerosing hemangioma. The patient recovered well and was discharged 2 weeks later. Hepatic sclerosing hemangioma is an extremely rare disease that can be easily mistaken for malignant liver tumors due to absence of typical imaging presentations. The diagnosis also needs to be differentiated from other benign tumors, such as liver adenoma and liver abscess, according to the medical history, symptoms, and auxiliary examinations. Therefore, special attention should be given to the diagnosis and treatment of sclerosing hemangioma.

Dermatofibroma Versus Dermatofibrosarcoma Protuberans: A Nuclear Morphology Study.

ABSTRACT: The locally invasive soft-tissue sarcoma, dermatofibrosarcoma protuberans (DFSPs), shares certain histologic features of the much more common and benign dermatofibroma (DF). While immunohistochemical stains, specifically cluster of differentiation 34 and Factor XIIIa, can be used to distinguish the 2 entities using microscopy, these markers are not entirely sensitive nor specific. Three-dimensionally, DFSP nuclei resemble a "puck" or "coin"-like shape. As hematoxylin/eosin-stained slides are prepared, these "puck" nuclei are fixed in an infinite number of orientations depending on their current position in rotation about their axes within the tumor cells. Under histological examination, this random nuclear positioning produces the appearance of 2 predominate morphologies: an ovoid "disk" shape (en face) and a narrow spindled shape (side view), which distribute in a roughly 50:50 ratio throughout the tumor sample slide. Nuclear morphology was analyzed in 324 DFSP and DF samples at high magnification (×400) to determine the presence or absence of a predominant morphology in which nuclei appear to alternate between an ovoid (en face) and spindled (side view) throughout most of the tumor sample. An alternating ovoid-spindled nuclear morphology was the predominant cytology in 98% of DFSP and was not predominant in 100% of DF samples (P < 0.001). This morphology was found to be highly specific (Sp = 1) and sensitive (Sn = 0.98) for DFSP. This unique nuclear morphology may be a more sensitive and specific diagnostic tool in identifying DFSP from DF in comparison with costly immunohistochemical stains.