Benign Mesenchymal Tumors Research Articles

Angiomyxoma of the Breast: A Clinicopathologic Analysis of 40 Cases.

Superficial angiomyxoma is an uncommon benign mesenchymal neoplasm that usually arises in dermis/subcutis of the extremities or trunk. Some tumors are associated with Carney complex. When arising in breast, these tumors are not well-recognized, mainly due to a lack of uniform nomenclature in the literature. This study therefore aims to improve recognition of angiomyxomas of the breast region. Forty cases were identified: demographics, presence of Carney complex, imaging and histologic features, PRKAR1A expression, and outcomes were evaluated. There were 22 female and 18 male patients (median age 40years, range: 14 to 72). Most tumors presented as slowly-growing masses (77%). All but one were solitary, and median size was 1.5cm. Tumors were superficial (dermal/subcutaneous) in 52.5% and deep/parenchymal in 47.5%. Nine involved the nipple-areola complex. All showed characteristic features of superficial angiomyxoma: poorly circumscribed, hypocellular, myxoid neoplasms with lobulated (55%) or infiltrative (45%) architecture, bland spindled fibroblasts, prominent thin-walled vessels, and admixed neutrophils. Tumors involving the nipple-areola complex infiltrated through areolar smooth muscle, and deep/parenchymal tumors showed entrapment of lobules mimicking myxoid fibroadenoma. Mitoses were typically absent, as was significant atypia. Cystic change was common. Two-thirds showed loss of PRKAR1A expression by immunohistochemistry. Two patients had Carney complex (7%). Recurrence after incomplete excision occurred in 1 patient. Angiomyxoma of breast may arise at superficial, nipple-areola or deep/parenchymal locations, where it can be difficult to recognize classic histologic features. Loss of expression of PRKAR1A is not invariable, but may be a helpful diagnostic clue. Recognizing angiomyxoma is important for 2 reasons: first, the recurrence rate is low and therefore wide excision is not essential, and second, it may allow detection of Carney complex in some patients.

Endoscopic endonasal resection of a primary intraosseous clival myxoma: illustrative case.

An intraosseous myxoma is a rare, benign mesenchymal tumor that penetrates the bone. The occurrence of an intraosseous myxoma in the clivus is a unique presentation of the disease. The authors discuss the case of a 15-year-old male with a new diagnosis of a primary clival intraosseous myxoma presenting with cranial nerve VI palsy. This is the third documented case of this pathology occurring in the clivus. This patient was successfully treated with endoscopic endonasal resection of the tumor. Primary clival intraosseous myxomas are extremely rare, but nonetheless it is important to add it to the differential diagnosis of clival masses. This mass has a high risk of recurrence, and prior literature suggests gross total resection may improve chances of progression-free survival. However, further larger studies are needed to provide guidelines regarding proper management of this pathology.

Superficial vaginal myofibroblastoma with mushroom-like appearance: A case report with colposcopic findings and literature review

Superficial myofibroblastoma (SMF) of the lower female genital tract is a relatively rare benign mesenchymal tumor. The diagnosis is usually challenging as it shares several similar clinicopathological features with other tumors. Herein, we present a case of a 71-year-old Chinese female patient with postmenopausal vaginal bleeding. Colposcopy imaging revealed a well-circumscribed mass in the vagina with a wide pedicle, resembling a mushroom. The patient underwent surgery, and the tumor was histologically diagnosed as SMF. To the best of our knowledge, this is the first report of colposcopic imaging of a superficial vaginal myofibroblastoma. In this case study, we review the clinicopathological features of SMF of the lower female genital tract reported in the literature to improve the understanding of the disease.

Case report on surgical removal of 3.5 kg benign mesenchymal tumor from the mandible region

BackgroundBenign mesenchymal tumors are rare tumors accounting for 5% of all salivary gland tumors and less than 10% of submandibular or sublingual gland tumors.Case presentationThe present case study represents a rare case of large-size benign mesenchymal tumors arising from the mandible region. The patient comes with the complaint of prominent swelling on the right side of the lower jaw. Clinical history revealed that the swelling appeared around 5 years ago and enhanced over time to form a large tumor. The patient presented with signs of anemia and hypoproteinemia, which were developed due to dysphagia and bleeding in the tumor. A worm infestation was also found during the clinical examination, and severe pain, foul smell, fungating tumor, frequent pus discharge, and bleeding were also reported. The patient was treated by surgical removal of tumors within 8 h of surgery. Right segmental mandibulectomy with wide local tumor excision was performed under general anesthesia and prophylactic tracheostomy to maintain a secure airway. A huge defect of 8 cm × 6 cm was generated on the right side of the face after tumor removal, which was repaired with the help of local advancement flap reconstruction. The tumor size was 30 cm × 20 cm with a weight of 3.5 kg.ConclusionTo our best knowledge, the present study is the first in the literature that has reported such a large tumor in the mandible region. The success of surgery presented in the current case is very rare to achieve in developing countries. By reporting the detailed procedures, the present case study will help increase the misdiagnosis, improper treatment, treatment delays, or associated complications.

Persistently Augmented FGF-23 Serum Values in a Surgically Resolved Oncogenic Osteomalacia Patient with No Tumor and Inflammatory Activity

Objective: Oncogenic osteomalacia is a paraneoplastic syndrome characterized by severe hypophosphatemia, hyperphosphaturia, and osteomalacia subordinated to renal loss of phosphate. It is caused by overproduction of phosphatonin fibroblast growth factor-23 by benign mesenchymal tumors which, when surgically eliminated, returns to basal levels. Methods: We report a case of a patient with oncogenic osteomalacia from a sacrum mesenchymal tumor whose FGF-23 levels remain elevated two years after successful surgical treatment. Results: A 53-year-old man with severe difficulty to walk and stand, severe hypophosphatemia, hyperphosphaturia, and raised levels of alkaline phosphatase and FGF-23 was diagnosed with oncogenic osteomalacia after a thorough process of elimination of causes of hyphosphatemia were excluded. Despite systemic chemotherapy, surgical removal of sacrum, primary mesenchymal tumor, phosphate and calcium supplementation, and no evidence of tumor recurrence, the serum concentration of FGF-23 remains elevated two years after discharge. Conclusions: The possible underlying mechanisms of sustained FGF-23 serum concentrations in this patient suggest the presence of molecular alterations in the FGF/FGFR signaling pathway.

Vulvar angiomyofibroblastoma is molecularly defined by recurrent MTG1-CYP2E1 fusions.

Angiomyofibroblastoma (AMF), a rare benign vulvovaginal mesenchymal tumour, poses a diagnostic challenge due to histologic and immunohistochemical overlap with other vulvar mesenchymal tumours. Recently, MTG1-CYP2E1 fusion transcripts were reported in 5/5 AMFs; no other genetic alterations have been described to date. Herein, we sought to investigate the frequency of the MTG1-CYP2E1 fusion and the presence of other potential genetic alterations in a cohort of AMFs (n = 7, patient age range: 28-49 years). Tumours demonstrated classic morphologic features including alternating hypo/hypercellular areas, capillary channels surrounded by epithelioid/spindled tumour cells, and variable amounts of mature adipose tissue. reverse transcription-polymerase chain reaction (RT-PCR) for MTG1-CYP2E1 fusion, performed in all seven cases, showed the fusion transcript in five of six cases (one case with technical failure). Two tumours, including the one lacking the fusion, were subjected to targeted next-generation sequencing (104 genes) and a sarcoma fusion assay (28 genes); the fusion negative AMF also underwent RNA sequencing. No additional mutations, copy number alterations, or fusion genes were identified with the assays employed. We conclude that the majority of AMFs harbour recurrent MTG1-CYP2E1 fusion transcripts and identification of this fusion may aid in the diagnosis.

Glomic Tumour of the Stomach: A Rare Cause of Anaemia.

Glomus tumour is a rare benign mesenchymal neoplasm most commonly found in the extremities.Gastric glomus tumour (GGT) is rare and its symptoms unspecific.The diagnosis of GGT relies on histology and immunohistochemistry as imaging lacks accuracy.Treatment is usually surgical but follow-up should be considered due to its malignant potential.

Bilateral vulvar lipomas in a premenopausal woman: A case report

Vulvar lipomas are benign mesenchymal neoplasms that are usually well defined, small and painless. They closely resemble the pathology and presentation of lipomas at other sites. They are commonly found in young and middle-aged women but can also be diagnosed in infants. A case of bilateral vulvar lipomas in a 37-year-old woman is reported. The diagnosis was made clinically and confirmed via surgical excision and histopathology.

S3609 Gastric Schwannoma in a Patient With Early Satiety

Introduction: Schwannomas are an uncommon subtype of benign gastrointestinal mesenchymal tumor found most frequently in the stomach originating from the Auerbach myenteric nerve plexus. Gastric schwannoma is frequently mistreated as it shares many similarities with GIST. We present the case of a patient with early satiety and iron deficiency anemia who was found to have gastric schwannoma on upper endoscopy. Case Description/Methods: A 59-year-old female with endometriosis and iron deficiency anemia on oral iron supplementation presented to our clinic with complaints of fatigue, frequent post-prandial cough, early satiety, and dark stools. She reported chronic NSAID use and denied abdominal pain, dysphagia, nausea, and unexplained weight loss. Initial CBC demonstrated a hemoglobin of 9.2 g/dL with positive stool guaiac testing. Cessation of NSAIDs led to hemoglobin improvement within normal limits. EGD revealed a roughly 5 cm smooth submucosal mass in the distal gastric body along the greater curvature with firm consistency and a central depression (Figure A). Colonoscopy was unremarkable. Abdominal CT demonstrated an exophytic mass within the gastric wall with relatively homogenous attenuation and enhancement (Figure B). Endoscopic ultrasound with FNA of the mass revealed pathology suspicious for a stromal cell neoplasm and elective laparoscopic partial gastrectomy was performed with findings of a 4.7 x 3.7 x 3.6 cm submucosal mass consistent with schwannoma with Sox10/S100 positivity and DOG-1/c-KIT negativity. The patient resumed a normal diet 2 days after surgery without complications. Discussion: Gastric schwannoma is frequently misdiagnosed as GIST due to similar prevalence, clinical symptoms, and appearance. Some studies suggest a misdiagnosis rate of up to 96.7%. Key to the diagnosis is the presence of S-100 positivity in schwannoma as GIST is negative for this marker. Additionally, DOG-1 and c-KIT are markers positive in GIST but negative in schwannoma. Most gastrointestinal schwannomas are solitary with sizes ranging from < 1 cm to 28 cm. Endoscopic ultrasound with FNA biopsy is recommended to increase chances of preoperative diagnosis by approximately 10%. Treatment modalities vary based on tumor size, with endoscopic resection suggested for tumors < 3 cm in diameter and surgical excision for larger sized masses. Malignant transformation is extremely rare occurring in roughly 2% of cases with S-100 expression decreasing as dedifferentiated Schwann cells form.Figure 1.: A. Endoscopic appearance of schwannoma as a smooth exophytic submucosal mass with central depression seen along the greater curvature of distal gastric body. B. Abdominal CT demonstrating luminal compression of the gastric body by a schwannoma with relatively homogenous attenuation and enhancement.

S3595 Gastric Glomus Tumors: Silent Until Ulcerated

Introduction: Glomus tumors are rare and mostly benign mesenchymal neoplasms comprising fewer than 2% of all soft tissue tumors. They arise from the modified smooth muscle cells (glomus cells) of the glomus body, an arteriovenous shunt typically found in peripheral soft tissue of the extremities. Rarely, glomus tumors can occur in the gastrointestinal (GI) tract, where they arise from the submucosa or muscularis propria. We present two interesting cases of gastric glomus tumor (GGT) with different clinical outcomes. Case Description/Methods: A 46-year-old female presented with shortness of breath and fatigue for 3 months. Labs showed iron deficiency anemia with a hemoglobin of 4.4 gm/dl. Esophagogastroduodenoscopy (EGD) revealed a large, ulcerated, partially circumferential mass in the gastric (Figure 1A, 1B) Imaging showed a solid 7.8 cm mass in the gastric antrum with multiple hepatic metastases. Gastric biopsy showed glomus tumor, with a positive smooth muscle actin (SMA) stain and abundant background necrosis. Liver biopsy also confirmed metastasis of the glomus tumor. Patient is currently undergoing chemotherapy to downsize the primary tumor before surgical intervention. A 72-year-old female with a history of breast cancer was admitted with hematemesis and melena. EGD revealed a large submucosal ulcerated gastric mass with signs of bleeding. Endoscopic ultrasound (EUS) showed the mass was arising from the muscularis propria, in the antrum of the stomach (Figure 2A, 2B) Fine needle aspiration was performed which expressed only synaptophysin (Syn), suggestive of gastric neuroendocrine tumor. Patient underwent an exploratory laparotomy and distal gastrectomy for continued GI bleeding. The tumor was sent for surgical pathology, which expressed both smooth muscle actin and Syn, confirming glomus tumor. The patient was stable following gastrectomy. Discussion: GGTs account for approximately 1% of all GI mesenchymal tumors and are difficult to differentiate from other richly vascularized tumors, such as gastrointestinal stromal tumor (GIST). The definitive diagnosis relies on EGD, histopathologic examination with immunohistochemical staining and EUS-guided fine-needle aspiration. Glomus tumor cells stain positive for SMA and vimentin, while Syn and CD34 can be positive in some cases. Surgical resection is the treatment of choice and offers a favourable prognosis. Metastatic spread as seen in one of our cases is extremely rare. There are no standard of care chemotherapeutic regimens for treatment of GGTs.Figure 1.: Two gastric glomus tumors seen on esophagogastroduodenoscopy (EGD) and endoscopic ultrasound (EUS).

S2080 Mucosal Schwann Cell Hamartoma of the Sigmoid Colon in a Transgender Female to Male on Testosterone Therapy: A Case Report

Introduction: Mucosal Schwann cell hamartomas of the gastrointestinal tract are rare benign mesenchymal neoplasms, of which the exact incidence within the population is unknown. First described as a new entity in 2009 by Gibson and Hornick1 in a retrospective case study examining pathology from 26 patients, it is suspected that the increase in incidence of colonic mucosal Schwann cell hamartomas is due to the increase of colorectal cancer screening. As of 2020, there have been 41 documented cases of Schwann cell hamartomas.2 Case Description/Methods: A 63-year-old transgender female to male on testosterone therapy for 10 years and history of adenomatous colon polyps 3 years prior presented for outpatient surveillance colonoscopy. The patient had no personal or family history of neurofibromatosis type 1 (NF1), Cowden syndrome, or multiple endocrine neoplasia (MEN) type 2b. Colonoscopy was notable for a 1 mm sessile polyp in the sigmoid colon (Figure 1) and 4 mm sessile ascending colon polyp. Review of the pathology demonstrated a tubular adenoma without dysplasia in the ascending colon, and in the sigmoid colon S-100 positive spindle cells with elongated nuclei and dense eosinophilic cytoplasm, consistent with a mucosal Schwann cell hamartoma (Figures 2 and 3). Discussion: Our patient presented for routine surveillance colonoscopy and was found to have a rare benign mesenchymal neoplasm of the sigmoid colon, a Schwann cell hamartoma. Mucosal Schwann cell hamartomas are typically small, 1-8 mm, primarily located in the left colon, have a female predominance and an average age at presentation of 62.3 They are not associated with malignancy or inherited syndromes.1,4 The histological differential diagnosis includes schwannoma, neurofibroma, mucosal neuroma, ganglioneuroma, ganglioneurmatosis, perineurioma and GIST, making accurate diagnosis key to avoid unnecessary treatments.4 Interestingly, our patient found to have a mucosal Schwann cell hamartoma of the sigmoid colon is a transgender female to male on testosterone therapy, which to our knowledge has not previously been reported. Recent studies in animal models have suggested testosterone may promote the growth of colorectal adenomas.5 The role of sex hormones in development of these neoplasms has yet to be explored.Figure 1.: Endoscopic finding of a 1 mm sigmoid colon polyp.Figure 2.: Histologic features show spindle cell proliferation, elongated nuclei, and eosinophilic cytoplasm under hematoxylin and eosin-stained sigmoid colonic mucosa. This is consistent with a mucosal Schwann cell hamartoma.Figure 3.: Immunochemistry for S-100 spindle cells within the sigmoid colon. This stain further solidified the diagnosis of Schwann cell hamartoma.

S2135 Submucosal Myxoma: The Unusual and Unwanted Tumor Inside the Colon

Introduction: Myxomas are benign mesenchymal neoplasms of unknown etiology and those involving the gastrointestinal (GI) tract are extremely rare. We are presenting an interesting case of myxomas in the GI tract, specifically of a polypoid colonic mucosal myxoma. Mucosal colonic myxoma represents a newly identified mesenchymal polyp of the colon and pathologists and gastroenterologists should be aware of this diagnostic entity. Case Description/Methods: A 60-year-old female with a past medical history of hypothyroidism, hyperlipidemia, gout, anxiety, CKD, and tubular adenomas, presents to the endoscopy unit after being referred for an EMR resection. During the procedure, a large 1.8 cm subpedunculated polyp in the proximal transverse colon is identified via previously placed tattoo. The polyp undergoes Submucosal injection ‘Orise’ to lift the lesion. After successful lifting, a 27mm stiff snare was used to perform the hot snare resection. A hemoclip was placed to close the defect. The specimen/resected lesion was then removed via roth net. Microscopic examination performed shows a polypoid colonic mucosa with a tubulovillous proliferation lined by adenomatous epithelium. In the submucosa there is a collection of myxoid stroma with interspersed blood vessels, collagen fragments, and rare spindle cells. The spindle cells are positive for CD34 immunostain and negative for smooth muscle actin, S100, and CD117 immunostains. Alcian blue stain highlights the myxoid stroma. Patient was stable and discharged after having a successful procedure (Figure). Discussion: Myxoma is originated from mesenchymal tissue and is characterized by the loose textured slimy tissue ofstellate cells, reticulin fibers, and mucoid substance. It is mainly found in the skin, soft tissue, and heart. Tumors that originate from the submucosa tend to protrude into the intestinal lumen as pedunculated masses. Our patient was found to have a polypoid colonic mucosa with a tubulovillous proliferation lined by adenomatous epithelium. Submucosal colonic myxoma represents a newly identified mesenchymal polyp of the colon and pathologists and gastroenterologists should be aware of this diagnostic entity.Figure 1.: Large 1.8 cm subpedunculated polyp in the proximal transverse colon identified via previously placed tattoo. Submucosal injection of 'Orise'; was performed to lift the lesion .

S3687 Unusual Cause of Bleeding From an Underlying Glomus Tumor

Introduction: Glomus tumors (GTs) are rare, mostly benign mesenchymal neoplasm accounting for nearly 1% of all gastrointestinal soft tissue tumors. Commonly seen in distal extremities, they do rarely occur in the gastrointestinal tract where it most commonly involves the stomach, especially the antrum. These tumors lack specific symptoms and endoscopic findings making it hard to differentiate from other gastrointestinal submucosal tumors without resection. We present a rare case of gastric glomus tumor (GGT) in the antrum diagnosed in a patient presenting with melena. Case Description/Methods: 47-year- old male patient presented with melena. Upper endoscopy revealed a non-bleeding gastric ulcer with a visible vessel. Almost 3 cm submucosal lesion was seen at the site of the ulcer concerning for possible hematoma. Given the size of the lesion a follow up CT scan was performed 2 months later which showed persistent 3 cm submucosal circumscribed hyper enhancing lesion at the pylorus. The patient was then scheduled for endoscopic ultrasound which showed a hypoechoic lesion with discrete borders arising from the muscularis propria measuring 22 × 24 mm in maximal dimension. Fine needle biopsy of the lesion was performed using 22-gauge needle. Pathology revealed uniform round cells intimately associated with gaping vessels. The cells were reactive for vimentin and smooth muscle actin consistent with the diagnosis of glomus tumor. The patient was referred to surgery for excision (Figure 1). Discussion: Glomus tumor of the stomach arise from the intramuscular layer and often present as a solitary submucosal lesion. GGTs usually present with epigastric discomfort, hematemesis, melena, nausea or vomiting or rarely as an incidental finding. Endoscopic ultrasound typically shows hypoechoic circumscribed lesions mostly arising from the fourth layer of the stomach. However biopsies are rarely conclusive thus making preoperative diagnosis challenging. Given its rare malignant potential, wide local surgical excision is the treatment of choice.Figure 1.: Endoscopic ultrasound of a glomus tumor in the gastric antrum. Figure 2: Upper endoscopy of a glomus tumor with a central ulcer and visible vessel.

Myoglomus Tumor: Glomus Tumor with Prominent Smooth Muscle Differentiation

Glomus tumors are rare benign mesenchymal tumors with various subclassifications. This is a case of a 71-yearold female with a 1.0 cm painful, firm nodule on her right heel who underwent surgical resection. The tumor demonstrated glomus cells with prominent smooth muscle differentiation that stained positively for SMA and caldesmin. Though glomangiomyomas are defined as having both a smooth muscle and vascular component, they do not account for such extensive smooth muscle differentiation. This case report proposes a new entity to better define these such tumors as a myoglomus tumor.

Updates in Pathology for Retroperitoneal Soft Tissue Sarcoma.

Retroperitoneal tumors are extremely rare. More than 70% of primary retroperitoneal soft tissue tumors are malignant. The most common sarcomas in the retroperitoneum include liposarcomas and leiomyosarcoma, however other sarcomas, along with benign mesenchymal tumors, can occur. Sarcomas are a heterogenous group of tumors with overlapping microscopic features, posing a diagnostic challenge for the pathologist. Correct tumor classification has become important for prognostication and the evolving targeted therapies for sarcoma subtypes. In this review, the pathology of retroperitoneal soft tissue sarcomas is discussed, which is important to the surgical oncologist. In addition, less common sarcomas and benign mesenchymal tumors of the retroperitoneum, which may mimic sarcoma clinically and pathologically, are also discussed.

Isolated hypopharynx lipoma: a case presentation and literature review

BackgroundLipomas are the most common benign mesenchymal tumors. They are defined as subcutaneous neoplasms of mature adipocyte cells that can occur wherever fatty tissue is. Lipomas are rare in the upper aerodigestive tract. Usually asymptomatic, they may be painful, uncomfortable, or even life-threatening especially if voluminous and located in the upper aerodigestive tract.Case presentationA 67-year-old female patient has presented with dyspnea on mild effort and chronic orthopnea. The physical examination was normal while the fiber optic endoscopy revealed a submucosal round-shaped mass rising from the left side of the post-cricoid region. CT scan revealed a well-circumscribed fatty mass of the left piriform sinus for which the patient underwent an endoscopic transoral approach for a complete removal with good results.Discussion and conclusionPharyngeal lipomas are rare entities that might be life-threatening. Although clinical manifestations are not specific, imaging techniques, especially MRI, help set the diagnosis showing a fatty mass of the upper aerodigestive tract. However, pathology examination is crucial to rule out low-grade liposarcomas. Surgical management is not well-codified and has benefited from the development of endoscopic techniques.

A Rare Tumor of The Oral Mucosa, Myopericytoma: Case Report

Myopericytoma (MPC) is defined as a benign mesenchymal neoplasm consisting mostly of oval spindle-shaped myoid-like cells with perivascular growth. Apart from being a rare lesion in all anatomical regions of the body, it is extremely rare in the oral and maxillofacial region and only a limited number of cases have been reported in the literature. We present here the case of MPC in a 42-year-old female patient who had a painless, enlarging lesion in the anterior mandible. Intraoral examination of the lesion revealed a smooth, nonwhite, pedunculated, fibrotic, painless, and nonbleeding lesion in the lingual aspect of the anterior mandible. Histopathologic examination revealed a tumor consisting of spherical/nodular structures composed of spindle cells and hemangioperistomatous vascular structures in the form of staghorn. These tumor cells showed no signs of malignancy. On immunohistochemical examination, the tumor cells were positive for CD34 and SMA. SMA Protein was also focally positive in nodular structures formed by spindle cells and tumor stroma. S-100 protein was negative in the lesion. To our knowledge, this is the second case of MPC that occurred in the mandibular gingiva.

INTRAORAL PIGMENTED BENIGN FIBROUS HISTIOCYTOMA: AN UNUSUAL PRESENTATION

Benign fibrous histiocytoma (BFH) is a benign mesenchymal neoplasm that shows both fibroblastic and histiocytic differentiation. To date, about 65 oral BFH cases have been reported. Oral BFH most often affects middle-aged adults, with a female predilection. Several variants of BFH have been described, such as classical, aneurysmal, hemosiderotic, cellular, epithelioid, lipidized, clear cell, granular cell, myxoid, and signet-ring cell. A 56-year-old woman was referred for management of a painless lesion in the palate 6 years ago. After excisional biopsy, microscopic analysis showed a benign proliferation of spindle cells, arranged in a storiform pattern, associated with pigmented deposits, which were highlighted with Fontana-Masson and Perl's iron stains. Immunohistochemical analysis revealed positivity for vimentin, HLA-DR, CD68, CD163 and FXIIIa; pan-CK, EMA, α-SMA, GFAP, S-100, and CD34 were negative. Ki-67 highlighted scarce positive cells. The current case probably expands the microscopical spectrum of the hemosiderotic variant of BFH. Benign fibrous histiocytoma (BFH) is a benign mesenchymal neoplasm that shows both fibroblastic and histiocytic differentiation. To date, about 65 oral BFH cases have been reported. Oral BFH most often affects middle-aged adults, with a female predilection. Several variants of BFH have been described, such as classical, aneurysmal, hemosiderotic, cellular, epithelioid, lipidized, clear cell, granular cell, myxoid, and signet-ring cell. A 56-year-old woman was referred for management of a painless lesion in the palate 6 years ago. After excisional biopsy, microscopic analysis showed a benign proliferation of spindle cells, arranged in a storiform pattern, associated with pigmented deposits, which were highlighted with Fontana-Masson and Perl's iron stains. Immunohistochemical analysis revealed positivity for vimentin, HLA-DR, CD68, CD163 and FXIIIa; pan-CK, EMA, α-SMA, GFAP, S-100, and CD34 were negative. Ki-67 highlighted scarce positive cells. The current case probably expands the microscopical spectrum of the hemosiderotic variant of BFH.

LIPOMA OF THE FLOOR OF THE MOUTH: A CASE REPORT

Lipoma is the most frequent mesenchymal neoplasm but rare in the oral cavity, representing 1% to 4% of benign oral neoplasms. We report a case of 50-year-old female patient reporting a painless growth under the tongue present for 2 years. Intraoral examination revealed a sessile nodule of soft consistency, covered by an intact mucosa on the right anterior buccal floor, measuring approximately 1.5 × 1.5 cm. The clinical differential diagnosis included lipoma and other benign mesenchymal tumors. An excisional biopsy under local anesthesia was performed. The surgical specimen had a yellowish color and soft consistency and floated in the formalin solution. Microscopic examination showed mature adipocytes and a variable amount of collagen bundles and blood vessels. The diagnosis of lipoma was established. After 10 months of follow-up no recurrence was detected.

POLYMORPHOUS LOW-GRADE ADENOCARCINOMA: CASE REPORT

A 62-year-old White female patient presented to the stomatology clinic with a submucosal nodular lesion in a region of the lower right labial mucosa, asymptomatic, well delimited, circumscribed, movable, with a fibrous consistency, measuring 1 cm in diameter, with approximately 1 year of evolution. With the hypothesis of benign salivary gland neoplasm and benign mesenchymal neoplasm, an excisional biopsy was performed. Histologically, proliferation of cells organized in nests, ducts, and cords was observed, showing pale nuclei and evident nucleoli. The presence of mucous cells and cribriform areas and extracellular matrix, sometimes fibrous and other times hyaline, was noted. Immunohistochemically, cells were positive for cytokeratins 7 and 14, S-100, and p63 and focally positive for smooth muscle actin. The cell proliferation index measured by Ki-67 was less than 5%. In view of the clinical and microscopic characteristics, the diagnosis of low-grade polymorphous adenocarcinoma was closed. The patient was referred to the head and neck surgeon.