interesting cases

The process involves the paracorical T-zones. My working hypothesis would be actually the same as yours: diffuse paracortical T-cell hyperplasia. I would particularly pay attention if the hyperplastic process respects the lymph node capsule and would probably stain the slides for an FDC marker (CD21 or CD23) and, if available, for PD-1, jsut to get an idea on the distribution of the T-FH cells. A correlation with the clinical history (medication, infections) would be of interest as well.

Thank you. I will check the situation (external case).

Again a case demonstrating the importance of clinico-pathologic correlation. There is a massive expansion of the paracortical area, which is diffuse and nodular. I agree it is most probably reactive, but to what? Can you rule out a dermatopathic lymphadenitis?? Simple old fashioned melanin and iron stains might help to solve this question, as well as some clinical information, if obtainable.

The lymph node shows reactive paracortical (T-zone) expansion with nodular collections of plasmacytoid dendritic cells. Features are of a reactive process. Both early Kikuchi and SLE need to be excluded, among other causes.

I agree with Dr. Naresh. You do not need CD123 because histology is quite clear in this case. Clinical correlation and follow up will tell what is this about.

Thank you. After words of surgeon- any B symptoms, fever and regressing of cervical lymphadenopathy up to date. Etiology seems to be unclear.

i agre with Dr Hurwitz, but what about the apoptosis seen in the last image DC" bjeg. apopotosis in a lymphoproliferative process often heralds neoplastic transformation. Careful clinincal correlation and follow up is advised.

Apoptosis is typically present in most reactive collections of plasmacytoid dendritic cells. It is so common that it actually also helps confirm their etiology. It is like finding neutrophils with monocytoid B-cells.

Thanx. Maybe another possibility than " early early Kikuchi" does exist? MPO crescents are absent.

The last point: multiple S100+ histiocytes; single CD1a+ cells. There is no Fe deposition.

The S-100+ cells that you are seeing are interdigitating dendritic cells, which in reactive paracortex look just like shown in your S-100 image (similar distance from one positive cell to another, dendritic morphology can only partly be observed since it is bodies of the cells that are positive more than extensions). One CD1+ cell is usually one Langerhans cell. Rare Langerhans cells can be found in many conditions in the lymph nodes and are sometimes seen even in clusters (like in follicular lymphoma) and in such cases LCH diagnosis should not be made. CD1a is also reported to be expressed by some activated T-cells in th LN. When you have only one positive cell, it may be impossible to tell what it is.

I suggest clinical follow up with testing for HIV if clinical condition deteriorates.