OBJECTIVE: The aim of this report was to review oral follicular lymphoid hyperplasia, with emphasis on palatal lesions.
METHODS: A comprehensive search was performed on PubMed for case reports and case series of palatal follicular lymphoid hyperplasia published in the English language literature. Relevant data from collated articles was sought, including patient demographics, clinical manifestations, imaging modalities and findings, comorbidities, etiopathogenesis, lesional management, and lesional outcome. A new palatal case has also been provided to illustrate several features of this lesion.
RESULTS: In total, 32 cases were assembled to establish clinicopathologic correlations, representing the largest aggregation of published cases. Most of the affected patients were at least 60 years old and with a decisive female predilection. The majority of lesions were ≤ 3 cm, appearing as normal color, purple-red or red, and varied from soft to firm. Notably, 32% of palatal follicular lymphoid hyperplasias were associated with denture wear, and lesional recurrence was recorded in 16% of cases. To date, none of the reported cases of palatal follicular lymphoid hyperplasia has undergone malignant transformation.
CONCLUSIONS: Palatal follicular lymphoid hyperplasias often arise as a reactive process. Critical histopathologic and histochemical assessments are necessary to establish benignity. Postoperatively, clinicians should follow patients for at least 5 years for recurrence and remain vigilant for neoplastic change as several published accounts of non-oral follicular lymphoid hyperplasias have undergone malignant transformation, usually to lymphoma.

A 53-year-old female with primary biliary cholangitis was referred for the evaluation of a hepatic nodule identified during routine imaging. Ultrasonography revealed a homogeneous, hypoechoic, 18 mm nodule in segment 3 of the liver. On dynamic CT and MRI, the nodule showed mild enhancement at the hepatic artery-dominant phase. On diffusion-weighted images, the nodule exhibited pronounced hyperintensity with accompanying wedge-shaped perinodular hyperintensity (comet and comet-tail appearance). The nodule showed a portal perfusion defect on CT during arterial portography, and mild enhancement on CT during hepatic arteriography (CTHA). A nodular and wedge-shaped perinodular enhancement (comet and comet-tail appearance) in the CTHA was also clearly observed. The nodule demonstrated abnormal FDG uptake on 18F-FDG-PET/CT. An excisional biopsy was performed for histopathological diagnosis, and the nodule was diagnosed as reactive lymphoid hyperplasia (RLH). Diagnosing hepatic RLH by imaging is challenging due to its imaging findings overlapping with those of various malignant tumors, especially the nodular type of lymphomas, making differentiation particularly difficult. However, radiologists should note the perinodular early enhancement and the perinodular hyperintensity on diffusion weighted images, which are thought to be key imaging findings of RLH, along with other characteristics such as a single, small, homogeneous nodule with mild early enhancement and marked restricted diffusion. We propose to name the nodular lesion with perinodular early enhancement/hyperintensity on diffusion weighted images as \'comet and comet-tail appearances\'.

UNASSIGNED: Hepatic reactive lymphoid hyperplasia (RLH) is a rare benign lymphoproliferative lesion and a poorly understood disease. It is usually asymptomatic and incidental, but it is difficult to distinguish from hepatocellular carcinoma and metastatic liver tumor on imaging, and percutaneous biopsy is not sufficient to distinguish from low-grade malignant lymphoma and extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma), making diagnosis difficult.
UNASSIGNED: A 69-year-old woman came to our hospital for reexamination of pulmonary nodules followed by liver occupation. The lesions showed \"wash-in and wash-out\" on contrast-enhanced ultrasonography and magnetic resonance imaging. Enhanced magnetic resonance also showed annular envelope enhancement and limited diffusion on the ADC map during the delay period. Imaging revealed metastatic liver cancer, and the patient underwent a partial hepatectomy. However, the final histopathological diagnosis was RLH.
UNASSIGNED: If small isolated nodules are found in the liver of middle-aged and elderly female patients with no risk factors for liver malignancy, when the enhanced imaging suggests \"wash-in and wash-out\", further focus should be placed on whether the enhanced imaging shows perinodular enhancement and whether the DWI shows limited diffusion in MRI, in order to emphasize the possibility of liver RLH diagnosis.

Follicular lymphoid hyperplasia is a rare reactive benign lesion of the oral mucosa. This is also known as pseudolymphoma as the features mimic the malignant counterpart Follicular lymphoma. In present case, a 34 year old male patient came with a nodular swelling in the posterior-lateral left side of tongue. Medical or dental history was non contributory. Swelling was painless, well demarcated, and about peanut sized. The swelling was provisionally diagnosed as either neurilemmoma, mucocele, or traumatic fibroma. Complete excision was performed, and tissue was sent to a private laboratory. Histopathological findings seen were germinal centers having a core of monotonous cells of the same size and demarcated mantle area mimicking the lymphoma. Immunophenotyping revealed diffused positivity for kappa and lambda expressions. CD10 was diffusely positive in germinal centers and BCl 2 was positive in the mantle area while negative in germinal centers. The final diagnosis given was follicular lymphoid hyperplasia. The entity mentioned in the present paper is an unusual variant of the benign lymphoproliferative lesion and very few cases are reported in the tongue area. Thus, it is important to understand the nature of this benign lesion in all aspects to avoid diagnostic dilemmas due to its malignant mirroring characteristics.

A 70-year-old woman was referred to our hospital because of slight elevation of soluble interleukin-2 receptor (sIL-2R) and accumulation of 18F-fluorodeoxyglucose (FDG) in S8 of the liver on positron emission tomography. The mass was strongly suspected to be malignant because of contrast enhancement and enlargement in size of the mass, and suspicion of portal vein invasion. Hepatic S8 subsegmentectomy was performed for diagnostic and therapeutic purposes. Hematoxylin and eosin staining of the resected specimen showed small lymphocytes with no atypia and no formation of lymphoid follicles. Immunostaining showed CD3-positive cells in the interfollicular region and CD20-positive cells in the lymphoid follicles. Both CD10 and BCL-2 were negative in the follicular germinal center. CD138-positive plasma cells were observed and there was no light chain restriction. Based on polyclonal growth pattern of lymphocytes in the lymphoid follicles and interfollicular region, she was diagnosed with hepatic reactive lymphoid hyperplasia (RLH).Review of the English literature of hepatic RLH which referred to imaging findings yielded 23 cases, including this case. As a result, we suggest that liver biopsy should be performed for definitive diagnosis, when hepatic RLH is suspected by imaging findings and backgrounds.

T-cell-rich angiomatoid polypoid pseudolymphoma (TRAPP) is a rare and recently defined entity, conceptualized just over a decade ago. Recognition of TRAPP is important because it can be clinically and microscopically confused with low-grade cutaneous lymphomas and other vascular proliferations. We report a case of a 28-year-old male with a solitary 1.2 cm red polypoid papule on the middle posterior base of the neck. The histopathological examination revealed a well-circumscribed dermal nodular proliferation of banal-appearing lymphovascular spaces with plump endothelial cells. Immunohistochemical analysis showed a T-cell-rich infiltrate. The clinical-pathological differential diagnosis for TRAPP includes pyogenic granuloma, angiolymphoid hyperplasia (epithelioid hemangioma), acral pseudolymphomatous angiokeratoma of children, cutaneous lymphoid hyperplasia, and low-grade cutaneous lymphomas and lymphoproliferative disorders. We review the literature and discuss the key differentiating features between TRAPP and its common differential diagnoses.

BACKGROUND Jessner\'s lymphocytic infiltration of the skin (JLIS) is a rare and benign process of unknown cause. This disorder affects both sexes, most commonly in the young adult population. However, the demographic characteristics remain largely unknown, due to limited information. JLIS clinical presentation is heterogeneous; lesions can be indurated papular or erythematous plaques on the upper body. Symptoms are variable, from asymptomatic to pruritus and burning sensation. CASE REPORT A female patient aged 73 years presented with 10-day asymptomatic dermatosis on the left malar area after an insect sting. At the beginning, the lesion was clinically classified as an abscess and antibiotic therapy was prescribed with ciprofloxacin 500 mg every 12 hours for 5 days. However, due to the lack of clinical response, a biopsy was performed, which reported a predominantly lymphocytic nodular dermatitis. JLIS diagnosis was confirmed after laboratory and imaging tests. Intralesional infiltrations of triamcinolone (0.5 ml) twice within 15 days and mineral sunscreen 3 times a day were prescribed. After the treatment, the lesion had a complete resolution without recurrence to date. CONCLUSIONS The present case reports JLIS in an older woman who presented a complete healing resolution of the lesion without recurrences after triamcinolone intralesional infiltrations and sunscreen protection.

Pseudolymphoma (PSL) of the orbit is a benign lymphoid hyperplasia (LH). It is a rare disease with an extensive range of known causative agents. LH is further classified into \"reactive\" (RLH) and \"atypical\" (ALH) types. It clinically presents as a single or a few plaques and/or nodular lesions, particularly on the head, neck, and upper trunk. It must be differentiated from orbital malignant lymphoma. In this report, we present a case of a 58-year-old Pakistani female with an asymptomatic recurrent right periorbital swelling for three years. It was clinically diagnosed as an angiotensin-converting enzyme (ACE) inhibitor-induced angioedema as it responded to stopping the ACE inhibitor; however, after four months, the patient again started to develop right periorbital swelling. An incisional biopsy revealed perivascular and periadnexal infiltration of lymphocytes, plasma cells, and a few neutrophils along with pigmentary incontinence. The formation of multiple lymphoid follicles and infiltration by monomorphic lymphoid cells in deeper skeletal muscle fibers were also observed. Immunohistochemistry (IHC) showed polyclonality and low Ki-67 labeling (20%), corresponding to periorbital RLH. Our objective in this study is to highlight the importance of considering PSL as a differential diagnosis in periorbital swelling. We also suggest that recurrent angioedema may lead to PSL.

UNASSIGNED: Primary cutaneous marginal zone lymphoma (PCMZL) is a low-grade malignant B-cell lymphoma that originates from the skin. It often presents as erythematous solitary or multiple papules, nodules, and/or plaques. It is one of the 3 main subtypes of primary cutaneous B-cell lymphomas. PCMZLs are believed to develop from chronic antigenic stimulation such as from tick-borne bacteria, vaccines, tattoo pigment, or other foreign body. In addition, cutaneous lymphoid hyperplasia, a documented precursor to malignant PCMZL, often presents in response to areas of chronic inflammation. Cutaneous lymphoid hyperplasia and PCMZL share several clinical and histological similarities that require clinicopathologic suspicion, immunohistochemical ancillary studies, and histopathologic analysis to accurately differentiate the 2 entities. Although gene rearrangement studies have historically been of limited value in the diagnosis of PCMZL, recent studies investigating molecular markers have identified the presence of multiple genetic abnormalities that have helped to better characterize the disease and aid in diagnosis. In addition, newer studies have found associations between PCMZL and gastrointestinal disorders, including Helicobacter pylori and inflammatory bowel disorders. In this article, we describe a case of a 56-year-old patient with a history of ulcerative colitis presenting with chronic reactive lymphoid hyperplasia that transformed to primary cutaneous marginal zone lymphoma.

BACKGROUND: The diagnosis of lymphoma in routine diagnostics can be challenging due to clinical, morphological and immunphenotypical overlap with unusual reactive processes termed \"pseudolymphomas.\"
METHODS: 45-year-old male that underwent surgical debridement for a necrotizing fasciitis of the thigh with concomitant excision of a regional lymph node.
METHODS: The lymph node demonstrated an architecture-effacing activation and proliferation of lymphoblasts and was initially misdiagnosed as an aggressive lymphoma. Only in consideration of the clinical context and with the help of additional immunohistochemical and molecular analyses the final diagnosis of a reactive lymphadenopathy could be made.
METHODS: No further therapy was required after the final diagnosis of a reactive lymphadenopathy was made.
RESULTS: The clinical follow-up was unremarkable, with no evidence of residual disease after 6 months.
CONCLUSIONS: This case report adds the parafollicular activation and proliferation of blasts and plasmablasts in the drainage area of an active infection to the spectrum of \"pseudolymphomas\" and reiterizes the importance of placing histopathological findings in the proper context.