T cells are also present and can form rosettes around HRS cells but do so less frequently than in NLPHL and are absent in nearly a quarter of cases (Figure 7, G).
Distinguishing lymphocyte-rich classical Hodgkin lymphoma from NLPHL and PTGC has important prognostic and therapeutic consequences.
Role of EBV on C-HL pathogenesis has been well documented in the previous studies, but no such relation with any agent has been demonstrated for NLPHL .
Our case of composite neoplasia of KS and NLPHL has unique characteristics in several respects.
is in the differential diagnosis, a marker of follicular dendritic cells such as CD21 to evaluate for nodules, or a marker of follicular T cells such as PD1 to evaluate for rosettes around the large cells, may be helpful.
18-20) Morphologically, the differential diagnosis between florid PTGCs and NLPHL can occasionally be challenging.
The samples included 11 cases of NLPHL and 5 cases of FH with prominent PTGCs (ie, enlarged nodules at least twice the size of surrounding germinal centers, containing residual germinal center elements among a proliferation of small lymphocytes with an obscure mantle zone boundary, representing >10% of follicles in a longitudinal section), as well as 8 cases of FH without PTGCs as negative controls.
To assess BCL6 protein expression, immunohistochemistry for BCL6 (Dako) was performed in NLPHL cases using an automated immunohistochemistry protocol (Ventana Medical Systems, Tucson, Arizona) with standard 5-im paraffin sections.
Characteristics of patients with NLPHL (age, sex, and site of biopsy) are listed in the Table.
On higher magnification, the nodules in NLPHL are typically composed of small B lymphocytes and variable numbers of larger atypical cells.
While the classic morphologic features are essential in diagnosing NLPHL, immunohistochemistry is very helpful in confirming the initial histopathologic impression.
Progressive transformation of germinal centers (PTGC) can mimic NLPHL clinically and histologically.