The fine needle aspiration appearances of Kikuchi’s lymphadenitis

Multiple Painless Cervical Lymphadenopathies Misleading the Diagnosis of Kikuchi's Disease

Kikuchi's disease is an unusual and self-limited disease. It manifests as a painful cervical lymphadenopathy and is associated with a low-grade fever and night sweats. Recently, this disease has been reported worldwide, compared to its initial high prevalence among the Japanese population. The etiologies of Kikuchi's disease are still unknown, but it has been proposed to have either infectious or immunological causes. We report the atypical presentation of a young male with Kikuchi's disease. A 22-year-old male presented with a prolonged fever for a week, which was associated with bilateral neck swelling that was painless and gradually increased in size. In our case, histopathological examination of the left cervical lymph node revealed histiocytic necrotizing lymphadenitis in favor of Kikuchi's disease. This case report will highlight the atypical clinical presentation of this patient, thereby increasing awareness of the disease's future manifestation.

Pitfalls in Lymph Node Fine Needle Aspiration Cytology

BACKGROUND

Fine needle aspiration cytology (FNAC) is an accurate, minimally invasive, and cost-effective biopsy method for enlarged lymph nodes. While the role of lymph node FNAC in the diagnosis of infectious or reactive conditions and metastatic malignancy is unquestioned, differing views still exist on its role in the diagnosis of lymphoma. Nevertheless, regardless of the practice setting, pitfalls and potential for error exist, and it is incumbent upon the pathologist to be aware of these pitfalls, as this is the first line of defence against errors.

SUMMARY

This discussion will focus on potential interpretational errors, specifically highlighting scenarios leading to false-negative and false-positive diagnosis and errors in tumour classification, with an emphasis on cytomorphology. Potential entities that may fly below the radar of the pathologist - so-called off-radar entities - are also discussed, as a reminder to consider broad differentials in cases with unusual morphologic features. Some reasons for false-negative diagnoses include low-grade lymphomas that mimic a mixed, polymorphous reactive lymphoid population or aspirates with a paucity of lesional cells, through either sampling error or the intrinsic nature of the entity, e.g., nodular lymphocyte predominant Hodgkin lymphoma. Some of the potential causes of false-positive diagnoses that are discussed include viral-associated lymphadenopathy, Kikuchi-Fujimoto lymphadenitis, or benign adnexal lesions mimicking metastatic malignancy. Errors in tumour classification covered include metastatic carcinoma, sarcoma, melanoma, and lymphoma mimicking each other, and Hodgkin lymphoma and its mimics. Finally, less common entities such as follicular dendritic cell sarcoma and others are briefly mentioned, to remind us of conditions that may slip under our diagnostic radar.

KEY MESSAGES

A systematic review of diagnostic pitfalls and traps is elucidated here, with some tips to avoid these traps. The triple approach to the diagnostic workup is emphasised, which includes rigorous clinicopathologic correlation, attention to cytomorphology, and judicious application of ancillary tests.

Kikuchi-Fujimoto disease: A comprehensive review

Kikuchi-Fujimoto disease, a rare form of necrotizing lymphadenitis, is an uncommon, benign, self-limiting disorder of obscure etiology. It affects mostly young adults of both genders. Clinically, it presents with fever and lymphadenopathy of a firm to rubbery consistency frequently involving cervical lymph nodes while weight loss, splenomegaly, leucopenia, and elevated erythrocyte sedimentation rate feature in severely affected patients. Cutaneous involvement occurs in about 30%-40% of cases as facial erythema and nonspecific erythematous papules, plaques, acneiform or morbilliform lesions of great histologic heterogeneity. Both Kikuchi-Fujimoto disease and systemic lupus erythematosus share an obscure and complex relationship as systemic lupus erythematosus may occasionally precede, develop subsequently, or sometimes be associated concurrently with Kikuchi-Fujimoto disease. It is often mistaken for non-Hodgkin lymphoma while lupus lymphadenitis, cat-scratch disease, Sweet's syndrome, Still's disease, drug eruptions, infectious mononucleosis, and viral or tubercular lymphadenitis are other common differentials. Fine needle aspiration cytology mostly has features of nonspecific reactive lymphadenitis and immunohistochemistry studies usually show variable features of uncertain diagnostic value. Since its diagnosis is exclusively from histopathology, it needs to be evaluated more carefully; an early lymph node biopsy will obviate the need for unnecessary investigations and therapeutic trials. Its treatment with systemic corticosteroids, hydroxychloroquine, or antimicrobial agents mostly remains empirical. The article reviews clinicoepidemiological, diagnostic, and management aspects of KFD from the perspective of practicing clinicians.

Efficacy of Ultrasound-Guided Needle Biopsy in the Diagnosis of Kikuchi-Fujimoto Disease

OBJECTIVES/HYPOTHESIS

Ultrasound-guided fine-needle aspiration cytology (US-FNAC) is a well-established procedure performed to establish the diagnosis of Kikuchi-Fujimoto disease (KFD). Ultrasound-guided core needle biopsy (US-CNB) is an alternative diagnostic tool for KFD. However, the efficacy of US-CNB is not well evaluated. This study aimed to evaluate the efficacy of US-CNB and compare it with that of US-FNAC in the diagnosis of KFD.

STUDY DESIGN

Retrospective cohort study.

METHODS

We analyzed 170 patients who were diagnosed with KFD between January 2009 and May 2019. US-FNAC, US-CNB, and excisional biopsy were performed in 47, 114, and 9 patients, respectively. Diagnostic accuracies of US-FNAC and US-CNB were analyzed and compared.

RESULTS

Of the 170 patients, 45 and 125 were men and women, respectively. The mean age was 26.9 ± 9.1 years. The most common symptom was cervical lymphadenopathy, followed by fever, headache, and myalgia. The diagnosis of KFD was established primarily by US-FNAC in 21 (44.7%) of the 47 patients, by US-CNB in 109 (95.6%) of the 114 patients, and by excisional biopsy in all 9 patients. There was no specific major complication related to US-FNAC and US-CNB.

CONCLUSION

US-CNB can be considered safe and effective and used as the primary modality for the pathological diagnosis of KFD.

LEVEL OF EVIDENCE

4. Laryngoscope, 131:E1519-E1523, 2021.

A Case of Kikuchi-Fujimoto Disease in a 7-Year-Old African American Patient: A Case Report and Review of Literature

Patient: Female, 7-year-old Final

Diagnosis: Kikuchi-Fujimoto lymphadenitis

Symptoms: Lymphadenopathy

Medication:—

Clinical Procedure: Biopsy

Specialty: Immunology • Rheumatology

Diagnosing Kikuchi's disease on fine needle aspiration biopsy

OBJECTIVE

To investigate the diagnostic utility of fine needle aspiration (FNA) smear, cell block (CB), flow cytometry (FC) and tuberculosis polymerase chain reaction (Tb-PCR) analysis for Kikuchi's disease (KD).

METHODS

A total of 173 FNA biopsy samples were collected using a Youyi aspirator. KD was diagnosed by FNA smear, with or without, CB, FC and Tb-PCR.

RESULTS

Out of 173 patients, 131 (75.7%) were female and 126 (72.8%) aged 21-40 years. Of these, 171 patients (98.8%) presented with painful enlarged cervical lymph nodes. All cytological samples identified intracellular apoptotic debris embedded in the cytoplasm of crescentic and phagocytic macrophages. In 24 cell-blocks (CBs), clusters of CD123 positive plasmacytoid monocytes were observed in KD. FC and CBs showed non-specific lymphoid hyperplasia in nine cases with suspicious lymphoma. Tb-PCR was negative in five cases with suspicion of tuberculosis.

CONCLUSIONS

In summary, FNA biopsy is a fast, reliable, and relatively inexpensive diagnosis tool for KD. CB preparation is an important adjunct method for the diagnosis of KD.

Expression of Epstein-Barr virus and granzyme B in cytologic smears of histiocytic necrotizing lymphadenitis

Histiocytic necrotizing lymphadenitis (HNL) is a non-neoplastic disease of the lymph nodes that is self-limiting in its clinical course. In this study, the expression of Epstein-Barr virus (EBV), granzyme B, and other phenotypic markers of HNL was investigated in fine needle-aspirated (FNA) cytologic smears obtained from 38 patients with HNL. The smear were subjected to immunohistochemical staining for granzyme B, CD3, CD4, CD8, CD20, and CD68 in addition to in-situ hybridization for EBV to determine whether marker expression could be correlated with disease pathogenesis. The mean age of 28 female and 10 male patients was 22.8 years. CD8-positive cytotoxic T cells were noted in 65.0% of the smears (13/20 cases), whereas CD4 and CD68 were rarely observed. Granzyme B reactivity was seen in lymphocytes, especially in apoptotic areas, and in histiocytes, with positive rates of 25.0% (9/36) and 11.1% (4/36), respectively. Most FNA smears showed immunoreactivity to both CD3 and CD20, with a predominance of CD3-positive cells. In-situ hybridization for EBV was positive in 22.9% (8/35) of the cases. The immunohistochemical staining and EBV in-situ hybridization results obtained in bleached FNA smears were similar to those in histologic sections. Overall, our results implicate that even though EBV positivity and granzyme B immunoreactivity are noted in HNL, they do not appear to have any apoptosis-associated role.

Cytologic features and frequency of plasmacytoid dendritic cells in the lymph nodes of patients with histiocytic necrotizing lymphadenitis (Kikuchi-Fujimoto disease)

Histiocytic necrotizing lymphadenitis (HNL), also known as Kikuchi-Fujimoto disease, is a benign and self-limiting disease. It is histologically characterized by nodal lesions that show the infiltration of histiocytes, lymphoid cells, myeloid dendritic cells (mDCs), and plasmacytoid dendritic cells (pDCs), along with either apoptotic or karyorrhexic nuclear debris. pDCs have been proposed to be lymphoid early-committed immature DCs which are positive for CD123, CD303, CD68, and HLA-DR but negative for fascin, a mature DC marker, as well as CD13 and CD33,which are mDC markers. In the present study, we analyzed the cytomorphologic features and frequency of pDCs in the lymph nodes of HNL patients. Because the cytologic apprearance of pDCs with Papanicolau staining was quite similar to that of large lymphocytes, immunocytochemistry against CD123 was necessary for the distinction of pDCs. Counting the number of CD123-positive pDCs in the HNL lymph nodes revealed that pDCs more frequently infiltrated the lymph nodes in the setting of HNL than in either reactive lymphadenitis or T and B cell lymphoma. In addition, interestingly, the numberof pDCs did not depend on the age of the HNL lesion, thus suggesting that pDCs are excellent indicators for the cytologic diagnosis of HNL.

Kikuchi-Fujimoto disease: three case reports

CONTEXT

Kikuchi-Fujimoto disease (KFD) manifests in most cases as unilateral cervical lymphadenomegaly, with or without accompanying fever. The disease mainly affects young women and has a self-limited course. It is more common in oriental countries, with few reports of its occurrence in Brazil. KFD should be included in the differential diagnosis of suspected cases of viral infections, tuberculosis, reactive lymphadenitis, systemic lupus erythematosus and metastatic diseases. It can be histologically confused with lymphoma. The disease is benign and self-limiting and an excisional biopsy of an affected lymph node is necessary for diagnosis. There is no specific therapy.

CASE REPORTS

This study reports on three cases of non-Asian female patients with KFD who were attended at our service between 2003 and 2006. A review of the literature was carried out, with a systematic search on this topic, with the aim of informing physicians about this entity that is manifested by cervical masses and fever.