Case 146

A 54-year-old female with a large uterine mass

1. What's the diagnosis?

   A: Fumarate hydratase deficient leiomyoma

   B: Dissecting leiomyoma

   C: Leiomyoma with bizarre nuclei

   D: Leiomyosarcoma

Answer

The correct answer is A.

Feature

Fumarate Hydratase–Deficient Leiomyoma

Also Seen In

Vascular pattern

Staghorn vasculature

Cellular and conventional leiomyomas【PMID:27454940】

Edema

Alveolar-pattern edema

Not specific

Nuclear atypia

Scattered bizarre nuclei; ovoid nuclei in chains

Leiomyoma with bizarre nuclei【PMID:28664937; 26457356】

Cytoplasmic features

Eosinophilic cytoplasmic (rhabdoid) inclusions

Occasionally in other leiomyomas【PMID:23211287】

Nucleoli

Prominent eosinophilic nucleoli surrounded by perinucleolar haloes

Rare in others

Specificity of features

Not entirely specific

Present in multiple leiomyoma variants

FH status

Loss of FH expression due to somatic or germline FH mutations (Hereditary Leiomyomatosis and Renal Cell Carcinoma – HLRCC syndrome)

Germline: associated with HLRCC; somatic: sporadic cases

Histologic overlap

Similar histology regardless of FH mutation mechanism

-

Case credit: UCSD Pathology

Author: Wangpan Jackson Shi, MD